[PATCHv3 00/35] Revamp the attr subsystem!

[PATCHv3 00/35] Revamp the attr subsystem!

[Stefan Beller]

previous discussion: https://public-inbox.org/git/20161028185502.8789-1-sbeller@google.com/

Changes since v2:
* dropped one patch (that exposes git_attr_counted, nobody uses
  it throughout the series )
* added pathspec guarding and added a test with git-add to see if it works.
* squashed "SQUASH" commits.
* changed test for multithreaded tests as git-status makes use of pathspec
  code that doesn't support this new magic yet. 

interdiff to currently queued at the bottom of this email.

v2 was:
previous discussion at https://public-inbox.org/git/20161022233225.8883-1-sbeller@google.com

This implements the discarded series':
jc/attr
jc/attr-more
sb/pathspec-label
sb/submodule-default-paths

This includes
* The fixes for windows
* Junios latest suggestion to use git_attr_check_initv instead of
  alloc/append.

* I implemented the thread safe attr API in patch 27 (attr: convert to new threadsafe API)
* patch 28 (attr: keep attr stack for each check) makes it actually possible
  to run in a multithreaded environment.
* I added a test for the multithreaded when it is introduced in patch 32
  (pathspec: allow querying for attributes) as well as a test to disallow
  multiple "attr"s in a pathspec.

Thanks,
Stefan


Junio C Hamano (23):
  commit.c: use strchrnul() to scan for one line
  attr.c: use strchrnul() to scan for one line
  attr.c: update a stale comment on "struct match_attr"
  attr.c: explain the lack of attr-name syntax check in parse_attr()
  attr.c: complete a sentence in a comment
  attr.c: mark where #if DEBUG ends more clearly
  attr.c: simplify macroexpand_one()
  attr.c: tighten constness around "git_attr" structure
  attr.c: plug small leak in parse_attr_line()
  attr: rename function and struct related to checking attributes
  attr: (re)introduce git_check_attr() and struct git_attr_check
  attr: convert git_all_attrs() to use "struct git_attr_check"
  attr: convert git_check_attrs() callers to use the new API
  attr: retire git_check_attrs() API
  attr: add counted string version of git_check_attr()
  attr: expose validity check for attribute names
  attr.c: add push_stack() helper
  attr.c: pass struct git_attr_check down the callchain
  attr.c: rename a local variable check
  attr.c: correct ugly hack for git_all_attrs()
  attr.c: introduce empty_attr_check_elems()
  attr.c: always pass check[] to collect_some_attrs()
  attr.c: outline the future plans by heavily commenting

Nguyễn Thái Ngọc Duy (1):
  attr: support quoting pathname patterns in C style

Stefan Beller (11):
  attr: make git_check_attr_counted static
  attr: convert to new threadsafe API
  attr: keep attr stack for each check
  Documentation: fix a typo
  pathspec: move long magic parsing out of prefix_pathspec
  pathspec: move prefix check out of the inner loop
  pathspec: allow querying for attributes
  pathspec: allow escaped query values
  submodule update: add `--init-default-path` switch
  clone: add --init-submodule=<pathspec> switch
  completion: clone can initialize specific submodules

 Documentation/config.txt                      |   5 +
 Documentation/git-clone.txt                   |  23 +-
 Documentation/git-submodule.txt               |  17 +-
 Documentation/gitattributes.txt               |  10 +-
 Documentation/glossary-content.txt            |  20 +
 Documentation/technical/api-gitattributes.txt | 140 ++++---
 archive.c                                     |  25 +-
 attr.c                                        | 517 ++++++++++++++++++--------
 attr.h                                        |  71 ++--
 builtin/check-attr.c                          |  74 ++--
 builtin/clone.c                               |  36 +-
 builtin/pack-objects.c                        |  27 +-
 commit.c                                      |   3 +-
 common-main.c                                 |   2 +
 contrib/completion/git-completion.bash        |   1 +
 convert.c                                     |  46 ++-
 dir.c                                         |  41 +-
 git-submodule.sh                              |  21 +-
 hashmap.h                                     |   2 +
 ll-merge.c                                    |  35 +-
 pathspec.c                                    | 228 ++++++++++--
 pathspec.h                                    |  19 +-
 t/t0003-attributes.sh                         |  26 ++
 t/t6134-pathspec-with-labels.sh               | 201 ++++++++++
 t/t7400-submodule-basic.sh                    | 134 +++++++
 userdiff.c                                    |  21 +-
 ws.c                                          |  19 +-
 27 files changed, 1354 insertions(+), 410 deletions(-)
 create mode 100755 t/t6134-pathspec-with-labels.sh

-- interdiff to current origin/sb/attr:

diff --git a/attr.c b/attr.c
index cf15e76..979bd3c 100644
--- a/attr.c
+++ b/attr.c
@@ -135,7 +135,7 @@ static void report_invalid_attr(const char *name, size_t len,
 	strbuf_release(&err);
 }
 
-struct git_attr *git_attr_counted(const char *name, size_t len)
+static struct git_attr *git_attr_internal(const char *name, int len)
 {
 	unsigned hval = hash_name(name, len);
 	unsigned pos = hval % HASHSIZE;
@@ -171,7 +171,7 @@ struct git_attr *git_attr_counted(const char *name, size_t len)
 
 struct git_attr *git_attr(const char *name)
 {
-	return git_attr_counted(name, strlen(name));
+	return git_attr_internal(name, strlen(name));
 }
 
 /* What does a matched pattern decide? */
@@ -259,7 +259,7 @@ static const char *parse_attr(const char *src, int lineno, const char *cp,
 		else {
 			e->setto = xmemdupz(equals + 1, ep - equals - 1);
 		}
-		e->attr = git_attr_counted(cp, len);
+		e->attr = git_attr_internal(cp, len);
 	}
 	return ep + strspn(ep, blank);
 }
@@ -320,7 +320,7 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 		      sizeof(struct attr_state) * num_attr +
 		      (is_macro ? 0 : namelen + 1));
 	if (is_macro) {
-		res->u.attr = git_attr_counted(name, namelen);
+		res->u.attr = git_attr_internal(name, namelen);
 		res->u.attr->maybe_macro = 1;
 	} else {
 		char *p = (char *)&(res->state[num_attr]);
diff --git a/attr.h b/attr.h
index e7534da..ab381ae 100644
--- a/attr.h
+++ b/attr.h
@@ -2,7 +2,7 @@
 #define ATTR_H
 
 /*
- * Must be called on platforms that do not support static initialisation
+ * Must be called on platforms that do not support static initialization
  * of mutexes.
  */
 extern void attr_start(void);
diff --git a/dir.c b/dir.c
index 3ec9117..c56d2ee 100644
--- a/dir.c
+++ b/dir.c
@@ -140,7 +140,8 @@ static size_t common_prefix_len(const struct pathspec *pathspec)
 		       PATHSPEC_LITERAL |
 		       PATHSPEC_GLOB |
 		       PATHSPEC_ICASE |
-		       PATHSPEC_EXCLUDE);
+		       PATHSPEC_EXCLUDE |
+		       PATHSPEC_ATTR);
 
 	for (n = 0; n < pathspec->nr; n++) {
 		size_t i = 0, len = 0, item_len;
@@ -349,7 +350,8 @@ static int do_match_pathspec(const struct pathspec *ps,
 		       PATHSPEC_LITERAL |
 		       PATHSPEC_GLOB |
 		       PATHSPEC_ICASE |
-		       PATHSPEC_EXCLUDE);
+		       PATHSPEC_EXCLUDE |
+		       PATHSPEC_ATTR);
 
 	if (!ps->nr) {
 		if (!ps->recursive ||
diff --git a/pathspec.c b/pathspec.c
index 8ea5dcb..d702803 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -232,6 +232,7 @@ static void eat_long_magic(struct pathspec_item *item, const char *elt,
 			char *attr_body = xmemdupz(body, len - strlen("attr:"));
 			parse_pathspec_attr_match(item, attr_body);
 			free(attr_body);
+			*magic |= PATHSPEC_ATTR;
 			continue;
 		}
 
diff --git a/pathspec.h b/pathspec.h
index ebef4bf..c2d046d 100644
--- a/pathspec.h
+++ b/pathspec.h
@@ -8,13 +8,15 @@
 #define PATHSPEC_GLOB		(1<<3)
 #define PATHSPEC_ICASE		(1<<4)
 #define PATHSPEC_EXCLUDE	(1<<5)
+#define PATHSPEC_ATTR		(1<<6)
 #define PATHSPEC_ALL_MAGIC	  \
 	(PATHSPEC_FROMTOP	| \
 	 PATHSPEC_MAXDEPTH	| \
 	 PATHSPEC_LITERAL	| \
 	 PATHSPEC_GLOB		| \
 	 PATHSPEC_ICASE		| \
-	 PATHSPEC_EXCLUDE)
+	 PATHSPEC_EXCLUDE	| \
+	 PATHSPEC_ATTR)
 
 #define PATHSPEC_ONESTAR 1	/* the pathspec pattern satisfies GFNM_ONESTAR */
 
diff --git a/t/t6134-pathspec-with-labels.sh b/t/t6134-pathspec-with-labels.sh
index 3d03e0a..5aafc0c 100755
--- a/t/t6134-pathspec-with-labels.sh
+++ b/t/t6134-pathspec-with-labels.sh
@@ -160,7 +160,23 @@ test_expect_success 'fail on multiple attr specifiers in one pathspec item' '
 '
 
 test_expect_success 'checking attributes in a multithreaded process' '
-	git status ":(attr:labelB)"
+	cat <<-EOF >expect &&
+	fileA:A
+	EOF
+	echo A >fileA &&
+	echo A >fileB &&
+	git grep A -- ":(attr:labelA)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'fail if attr magic is used places not implemented' '
+	# The main purpose of this test is to check that we actually fail
+	# when you attempt to use attr magic in commands that do not implement
+	# attr magic. This test does not advocate git-add to stay that way,
+	# though, but git-add is convenient as it has its own internal pathspec
+	# parsing.
+	test_must_fail git add ":(attr:labelB)" 2>actual &&
+	test_i18ngrep "unsupported magic" actual
 '
 
 test_expect_success 'abort on giving invalid label on the command line' '



-- 
2.10.1.469.g00a8914

[PATCH 01/35] commit.c: use strchrnul() to scan for one line

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 commit.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/commit.c b/commit.c
index 856fd4a..41b2fdd 100644
--- a/commit.c
+++ b/commit.c
@@ -415,8 +415,7 @@ int find_commit_subject(const char *commit_buffer, const char **subject)
 		p++;
 	if (*p) {
 		p = skip_blank_lines(p + 2);
-		for (eol = p; *eol && *eol != '\n'; eol++)
-			; /* do nothing */
+		eol = strchrnul(p, '\n');
 	} else
 		eol = p;
 
-- 
2.10.1.469.g00a8914

[PATCH 02/35] attr.c: use strchrnul() to scan for one line

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/attr.c b/attr.c
index eec5d7d..45aec1b 100644
--- a/attr.c
+++ b/attr.c
@@ -402,8 +402,8 @@ static struct attr_stack *read_attr_from_index(const char *path, int macro_ok)
 	for (sp = buf; *sp; ) {
 		char *ep;
 		int more;
-		for (ep = sp; *ep && *ep != '\n'; ep++)
-			;
+
+		ep = strchrnul(sp, '\n');
 		more = (*ep == '\n');
 		*ep = '\0';
 		handle_attr_line(res, sp, path, ++lineno, macro_ok);
-- 
2.10.1.469.g00a8914

[PATCH 03/35] attr.c: update a stale comment on "struct match_attr"

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

When 82dce998 (attr: more matching optimizations from .gitignore,
2012-10-15) changed a pointer to a string "*pattern" into an
embedded "struct pattern" in struct match_attr, it forgot to update
the comment that describes the structure.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/attr.c b/attr.c
index 45aec1b..4ae7801 100644
--- a/attr.c
+++ b/attr.c
@@ -131,9 +131,8 @@ struct pattern {
  * If is_macro is true, then u.attr is a pointer to the git_attr being
  * defined.
  *
- * If is_macro is false, then u.pattern points at the filename pattern
- * to which the rule applies.  (The memory pointed to is part of the
- * memory block allocated for the match_attr instance.)
+ * If is_macro is false, then u.pat is the filename pattern to which the
+ * rule applies.
  *
  * In either case, num_attr is the number of attributes affected by
  * this rule, and state is an array listing them.  The attributes are
-- 
2.10.1.469.g00a8914

[PATCH 04/35] attr.c: explain the lack of attr-name syntax check in parse_attr()

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/attr.c b/attr.c
index 4ae7801..05db667 100644
--- a/attr.c
+++ b/attr.c
@@ -183,6 +183,12 @@ static const char *parse_attr(const char *src, int lineno, const char *cp,
 			return NULL;
 		}
 	} else {
+		/*
+		 * As this function is always called twice, once with
+		 * e == NULL in the first pass and then e != NULL in
+		 * the second pass, no need for invalid_attr_name()
+		 * check here.
+		 */
 		if (*cp == '-' || *cp == '!') {
 			e->setto = (*cp == '-') ? ATTR__FALSE : ATTR__UNSET;
 			cp++;
-- 
2.10.1.469.g00a8914

[PATCH 05/35] attr.c: complete a sentence in a comment

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/attr.c b/attr.c
index 05db667..a7f2c3f 100644
--- a/attr.c
+++ b/attr.c
@@ -300,7 +300,7 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
  * directory (again, reading the file from top to bottom) down to the
  * current directory, and then scan the list backwards to find the first match.
  * This is exactly the same as what is_excluded() does in dir.c to deal with
- * .gitignore
+ * .gitignore file and info/excludes file as a fallback.
  */
 
 static struct attr_stack {
-- 
2.10.1.469.g00a8914

[PATCH 06/35] attr.c: mark where #if DEBUG ends more clearly

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/attr.c b/attr.c
index a7f2c3f..95416d3 100644
--- a/attr.c
+++ b/attr.c
@@ -469,7 +469,7 @@ static void debug_set(const char *what, const char *match, struct git_attr *attr
 #define debug_push(a) do { ; } while (0)
 #define debug_pop(a) do { ; } while (0)
 #define debug_set(a,b,c,d) do { ; } while (0)
-#endif
+#endif /* DEBUG_ATTR */
 
 static void drop_attr_stack(void)
 {
-- 
2.10.1.469.g00a8914

[PATCH 07/35] attr.c: simplify macroexpand_one()

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

The double-loop wants to do an early return immediately when one
matching macro is found.  Eliminate the extra variable 'a' used for
that purpose and rewrite the "assign the found item to 'a' to make
it non-NULL and force the loop(s) to terminate" with a direct return
from there.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/attr.c b/attr.c
index 95416d3..7bfeef3 100644
--- a/attr.c
+++ b/attr.c
@@ -701,24 +701,21 @@ static int fill(const char *path, int pathlen, int basename_offset,
 static int macroexpand_one(int nr, int rem)
 {
 	struct attr_stack *stk;
-	struct match_attr *a = NULL;
 	int i;
 
 	if (check_all_attr[nr].value != ATTR__TRUE ||
 	    !check_all_attr[nr].attr->maybe_macro)
 		return rem;
 
-	for (stk = attr_stack; !a && stk; stk = stk->prev)
-		for (i = stk->num_matches - 1; !a && 0 <= i; i--) {
+	for (stk = attr_stack; stk; stk = stk->prev) {
+		for (i = stk->num_matches - 1; 0 <= i; i--) {
 			struct match_attr *ma = stk->attrs[i];
 			if (!ma->is_macro)
 				continue;
 			if (ma->u.attr->attr_nr == nr)
-				a = ma;
+				return fill_one("expand", ma, rem);
 		}
-
-	if (a)
-		rem = fill_one("expand", a, rem);
+	}
 
 	return rem;
 }
-- 
2.10.1.469.g00a8914

[PATCH 08/35] attr.c: tighten constness around "git_attr" structure

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

It holds an interned string, and git_attr_name() is a way to peek
into it.  Make sure the involved pointer types are pointer-to-const.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 2 +-
 attr.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/attr.c b/attr.c
index 7bfeef3..5c35d42 100644
--- a/attr.c
+++ b/attr.c
@@ -43,7 +43,7 @@ static int cannot_trust_maybe_real;
 static struct git_attr_check *check_all_attr;
 static struct git_attr *(git_attr_hash[HASHSIZE]);
 
-char *git_attr_name(struct git_attr *attr)
+const char *git_attr_name(const struct git_attr *attr)
 {
 	return attr->name;
 }
diff --git a/attr.h b/attr.h
index 8b08d33..00d7a66 100644
--- a/attr.h
+++ b/attr.h
@@ -25,7 +25,7 @@ extern const char git_attr__false[];
  * Unset one is returned as NULL.
  */
 struct git_attr_check {
-	struct git_attr *attr;
+	const struct git_attr *attr;
 	const char *value;
 };
 
@@ -34,7 +34,7 @@ struct git_attr_check {
  * return value is a pointer to a null-delimited string that is part
  * of the internal data structure; it should not be modified or freed.
  */
-char *git_attr_name(struct git_attr *);
+extern const char *git_attr_name(const struct git_attr *);
 
 int git_check_attr(const char *path, int, struct git_attr_check *);
 
-- 
2.10.1.469.g00a8914

[PATCH 09/35] attr.c: plug small leak in parse_attr_line()

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

If any error is noticed after the match_attr structure is allocated,
we shouldn't just return NULL from this function.

Add a fail_return label that frees the allocated structure and
returns NULL, and consistently jump there when we want to return
NULL after cleaning up.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/attr.c b/attr.c
index 5c35d42..1877f7a 100644
--- a/attr.c
+++ b/attr.c
@@ -223,7 +223,7 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 		if (!macro_ok) {
 			fprintf(stderr, "%s not allowed: %s:%d\n",
 				name, src, lineno);
-			return NULL;
+			goto fail_return;
 		}
 		is_macro = 1;
 		name += strlen(ATTRIBUTE_MACRO_PREFIX);
@@ -233,7 +233,7 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 			fprintf(stderr,
 				"%.*s is not a valid attribute name: %s:%d\n",
 				namelen, name, src, lineno);
-			return NULL;
+			goto fail_return;
 		}
 	}
 	else
@@ -246,7 +246,7 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 	for (cp = states, num_attr = 0; *cp; num_attr++) {
 		cp = parse_attr(src, lineno, cp, NULL);
 		if (!cp)
-			return NULL;
+			goto fail_return;
 	}
 
 	res = xcalloc(1,
@@ -267,7 +267,7 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 		if (res->u.pat.flags & EXC_FLAG_NEGATIVE) {
 			warning(_("Negative patterns are ignored in git attributes\n"
 				  "Use '\\!' for literal leading exclamation."));
-			return NULL;
+			goto fail_return;
 		}
 	}
 	res->is_macro = is_macro;
@@ -283,6 +283,10 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 	}
 
 	return res;
+
+fail_return:
+	free(res);
+	return NULL;
 }
 
 /*
-- 
2.10.1.469.g00a8914

[PATCH 10/35] attr: rename function and struct related to checking attributes

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

The traditional API to check attributes is to prepare an N-element
array of "struct git_attr_check" and pass N and the array to the
function "git_check_attr()" as arguments.

In preparation to revamp the API to pass a single structure, in
which these N elements are held, rename the type used for these
individual array elements to "struct git_attr_check_elem" and rename
the function to "git_check_attrs()".

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 archive.c              |  6 +++---
 attr.c                 | 12 ++++++------
 attr.h                 |  8 ++++----
 builtin/check-attr.c   | 19 ++++++++++---------
 builtin/pack-objects.c |  6 +++---
 convert.c              | 12 ++++++------
 ll-merge.c             | 10 +++++-----
 userdiff.c             |  4 ++--
 ws.c                   |  6 +++---
 9 files changed, 42 insertions(+), 41 deletions(-)

diff --git a/archive.c b/archive.c
index dde1ab4..2dc8d6c 100644
--- a/archive.c
+++ b/archive.c
@@ -87,7 +87,7 @@ void *sha1_file_to_archive(const struct archiver_args *args,
 	return buffer;
 }
 
-static void setup_archive_check(struct git_attr_check *check)
+static void setup_archive_check(struct git_attr_check_elem *check)
 {
 	static struct git_attr *attr_export_ignore;
 	static struct git_attr *attr_export_subst;
@@ -123,7 +123,7 @@ static int write_archive_entry(const unsigned char *sha1, const char *base,
 	struct archiver_context *c = context;
 	struct archiver_args *args = c->args;
 	write_archive_entry_fn_t write_entry = c->write_entry;
-	struct git_attr_check check[2];
+	struct git_attr_check_elem check[2];
 	const char *path_without_prefix;
 	int err;
 
@@ -138,7 +138,7 @@ static int write_archive_entry(const unsigned char *sha1, const char *base,
 	path_without_prefix = path.buf + args->baselen;
 
 	setup_archive_check(check);
-	if (!git_check_attr(path_without_prefix, ARRAY_SIZE(check), check)) {
+	if (!git_check_attrs(path_without_prefix, ARRAY_SIZE(check), check)) {
 		if (ATTR_TRUE(check[0].value))
 			return 0;
 		args->convert = ATTR_TRUE(check[1].value);
diff --git a/attr.c b/attr.c
index 1877f7a..c99e23a 100644
--- a/attr.c
+++ b/attr.c
@@ -40,7 +40,7 @@ struct git_attr {
 static int attr_nr;
 static int cannot_trust_maybe_real;
 
-static struct git_attr_check *check_all_attr;
+static struct git_attr_check_elem *check_all_attr;
 static struct git_attr *(git_attr_hash[HASHSIZE]);
 
 const char *git_attr_name(const struct git_attr *attr)
@@ -665,7 +665,7 @@ static int macroexpand_one(int attr_nr, int rem);
 
 static int fill_one(const char *what, struct match_attr *a, int rem)
 {
-	struct git_attr_check *check = check_all_attr;
+	struct git_attr_check_elem *check = check_all_attr;
 	int i;
 
 	for (i = a->num_attr - 1; 0 < rem && 0 <= i; i--) {
@@ -730,7 +730,7 @@ static int macroexpand_one(int nr, int rem)
  * collected. Otherwise all attributes are collected.
  */
 static void collect_some_attrs(const char *path, int num,
-			       struct git_attr_check *check)
+			       struct git_attr_check_elem *check)
 
 {
 	struct attr_stack *stk;
@@ -758,7 +758,7 @@ static void collect_some_attrs(const char *path, int num,
 		rem = 0;
 		for (i = 0; i < num; i++) {
 			if (!check[i].attr->maybe_real) {
-				struct git_attr_check *c;
+				struct git_attr_check_elem *c;
 				c = check_all_attr + check[i].attr->attr_nr;
 				c->value = ATTR__UNSET;
 				rem++;
@@ -773,7 +773,7 @@ static void collect_some_attrs(const char *path, int num,
 		rem = fill(path, pathlen, basename_offset, stk, rem);
 }
 
-int git_check_attr(const char *path, int num, struct git_attr_check *check)
+int git_check_attrs(const char *path, int num, struct git_attr_check_elem *check)
 {
 	int i;
 
@@ -789,7 +789,7 @@ int git_check_attr(const char *path, int num, struct git_attr_check *check)
 	return 0;
 }
 
-int git_all_attrs(const char *path, int *num, struct git_attr_check **check)
+int git_all_attrs(const char *path, int *num, struct git_attr_check_elem **check)
 {
 	int i, count, j;
 
diff --git a/attr.h b/attr.h
index 00d7a66..dd3c4a3 100644
--- a/attr.h
+++ b/attr.h
@@ -20,11 +20,11 @@ extern const char git_attr__false[];
 #define ATTR_UNSET(v) ((v) == NULL)
 
 /*
- * Send one or more git_attr_check to git_check_attr(), and
+ * Send one or more git_attr_check to git_check_attrs(), and
  * each 'value' member tells what its value is.
  * Unset one is returned as NULL.
  */
-struct git_attr_check {
+struct git_attr_check_elem {
 	const struct git_attr *attr;
 	const char *value;
 };
@@ -36,7 +36,7 @@ struct git_attr_check {
  */
 extern const char *git_attr_name(const struct git_attr *);
 
-int git_check_attr(const char *path, int, struct git_attr_check *);
+int git_check_attrs(const char *path, int, struct git_attr_check_elem *);
 
 /*
  * Retrieve all attributes that apply to the specified path.  *num
@@ -45,7 +45,7 @@ int git_check_attr(const char *path, int, struct git_attr_check *);
  * objects describing the attributes and their values.  *check must be
  * free()ed by the caller.
  */
-int git_all_attrs(const char *path, int *num, struct git_attr_check **check);
+int git_all_attrs(const char *path, int *num, struct git_attr_check_elem **check);
 
 enum git_attr_direction {
 	GIT_ATTR_CHECKIN,
diff --git a/builtin/check-attr.c b/builtin/check-attr.c
index 53a5a18..97e3837 100644
--- a/builtin/check-attr.c
+++ b/builtin/check-attr.c
@@ -24,8 +24,8 @@ static const struct option check_attr_options[] = {
 	OPT_END()
 };
 
-static void output_attr(int cnt, struct git_attr_check *check,
-	const char *file)
+static void output_attr(int cnt, struct git_attr_check_elem *check,
+			const char *file)
 {
 	int j;
 	for (j = 0; j < cnt; j++) {
@@ -51,14 +51,15 @@ static void output_attr(int cnt, struct git_attr_check *check,
 	}
 }
 
-static void check_attr(const char *prefix, int cnt,
-	struct git_attr_check *check, const char *file)
+static void check_attr(const char *prefix,
+		       int cnt, struct git_attr_check_elem *check,
+		       const char *file)
 {
 	char *full_path =
 		prefix_path(prefix, prefix ? strlen(prefix) : 0, file);
 	if (check != NULL) {
-		if (git_check_attr(full_path, cnt, check))
-			die("git_check_attr died");
+		if (git_check_attrs(full_path, cnt, check))
+			die("git_check_attrs died");
 		output_attr(cnt, check, file);
 	} else {
 		if (git_all_attrs(full_path, &cnt, &check))
@@ -69,8 +70,8 @@ static void check_attr(const char *prefix, int cnt,
 	free(full_path);
 }
 
-static void check_attr_stdin_paths(const char *prefix, int cnt,
-	struct git_attr_check *check)
+static void check_attr_stdin_paths(const char *prefix,
+				   int cnt, struct git_attr_check_elem *check)
 {
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf unquoted = STRBUF_INIT;
@@ -99,7 +100,7 @@ static NORETURN void error_with_usage(const char *msg)
 
 int cmd_check_attr(int argc, const char **argv, const char *prefix)
 {
-	struct git_attr_check *check;
+	struct git_attr_check_elem *check;
 	int cnt, i, doubledash, filei;
 
 	if (!is_bare_repository())
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 1e7c2a9..3cb38ed 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -896,7 +896,7 @@ static void write_pack_file(void)
 			written, nr_result);
 }
 
-static void setup_delta_attr_check(struct git_attr_check *check)
+static void setup_delta_attr_check(struct git_attr_check_elem *check)
 {
 	static struct git_attr *attr_delta;
 
@@ -908,10 +908,10 @@ static void setup_delta_attr_check(struct git_attr_check *check)
 
 static int no_try_delta(const char *path)
 {
-	struct git_attr_check check[1];
+	struct git_attr_check_elem check[1];
 
 	setup_delta_attr_check(check);
-	if (git_check_attr(path, ARRAY_SIZE(check), check))
+	if (git_check_attrs(path, ARRAY_SIZE(check), check))
 		return 0;
 	if (ATTR_FALSE(check->value))
 		return 1;
diff --git a/convert.c b/convert.c
index 077f5e6..c95ae71 100644
--- a/convert.c
+++ b/convert.c
@@ -718,7 +718,7 @@ static int ident_to_worktree(const char *path, const char *src, size_t len,
 	return 1;
 }
 
-static enum crlf_action git_path_check_crlf(struct git_attr_check *check)
+static enum crlf_action git_path_check_crlf(struct git_attr_check_elem *check)
 {
 	const char *value = check->value;
 
@@ -735,7 +735,7 @@ static enum crlf_action git_path_check_crlf(struct git_attr_check *check)
 	return CRLF_UNDEFINED;
 }
 
-static enum eol git_path_check_eol(struct git_attr_check *check)
+static enum eol git_path_check_eol(struct git_attr_check_elem *check)
 {
 	const char *value = check->value;
 
@@ -748,7 +748,7 @@ static enum eol git_path_check_eol(struct git_attr_check *check)
 	return EOL_UNSET;
 }
 
-static struct convert_driver *git_path_check_convert(struct git_attr_check *check)
+static struct convert_driver *git_path_check_convert(struct git_attr_check_elem *check)
 {
 	const char *value = check->value;
 	struct convert_driver *drv;
@@ -761,7 +761,7 @@ static struct convert_driver *git_path_check_convert(struct git_attr_check *chec
 	return NULL;
 }
 
-static int git_path_check_ident(struct git_attr_check *check)
+static int git_path_check_ident(struct git_attr_check_elem *check)
 {
 	const char *value = check->value;
 
@@ -783,7 +783,7 @@ static const char *conv_attr_name[] = {
 static void convert_attrs(struct conv_attrs *ca, const char *path)
 {
 	int i;
-	static struct git_attr_check ccheck[NUM_CONV_ATTRS];
+	static struct git_attr_check_elem ccheck[NUM_CONV_ATTRS];
 
 	if (!ccheck[0].attr) {
 		for (i = 0; i < NUM_CONV_ATTRS; i++)
@@ -792,7 +792,7 @@ static void convert_attrs(struct conv_attrs *ca, const char *path)
 		git_config(read_convert_config, NULL);
 	}
 
-	if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
+	if (!git_check_attrs(path, NUM_CONV_ATTRS, ccheck)) {
 		ca->crlf_action = git_path_check_crlf(ccheck + 4);
 		if (ca->crlf_action == CRLF_UNDEFINED)
 			ca->crlf_action = git_path_check_crlf(ccheck + 0);
diff --git a/ll-merge.c b/ll-merge.c
index ad8be42..eb2c37e 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -336,13 +336,13 @@ static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr
 	return &ll_merge_drv[LL_TEXT_MERGE];
 }
 
-static int git_path_check_merge(const char *path, struct git_attr_check check[2])
+static int git_path_check_merge(const char *path, struct git_attr_check_elem check[2])
 {
 	if (!check[0].attr) {
 		check[0].attr = git_attr("merge");
 		check[1].attr = git_attr("conflict-marker-size");
 	}
-	return git_check_attr(path, 2, check);
+	return git_check_attrs(path, 2, check);
 }
 
 static void normalize_file(mmfile_t *mm, const char *path)
@@ -362,7 +362,7 @@ int ll_merge(mmbuffer_t *result_buf,
 	     mmfile_t *theirs, const char *their_label,
 	     const struct ll_merge_options *opts)
 {
-	static struct git_attr_check check[2];
+	static struct git_attr_check_elem check[2];
 	static const struct ll_merge_options default_opts;
 	const char *ll_driver_name = NULL;
 	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
@@ -398,12 +398,12 @@ int ll_merge(mmbuffer_t *result_buf,
 
 int ll_merge_marker_size(const char *path)
 {
-	static struct git_attr_check check;
+	static struct git_attr_check_elem check;
 	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 
 	if (!check.attr)
 		check.attr = git_attr("conflict-marker-size");
-	if (!git_check_attr(path, 1, &check) && check.value) {
+	if (!git_check_attrs(path, 1, &check) && check.value) {
 		marker_size = atoi(check.value);
 		if (marker_size <= 0)
 			marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
diff --git a/userdiff.c b/userdiff.c
index 2125d6d..4de3289 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -263,7 +263,7 @@ struct userdiff_driver *userdiff_find_by_name(const char *name) {
 struct userdiff_driver *userdiff_find_by_path(const char *path)
 {
 	static struct git_attr *attr;
-	struct git_attr_check check;
+	struct git_attr_check_elem check;
 
 	if (!attr)
 		attr = git_attr("diff");
@@ -271,7 +271,7 @@ struct userdiff_driver *userdiff_find_by_path(const char *path)
 
 	if (!path)
 		return NULL;
-	if (git_check_attr(path, 1, &check))
+	if (git_check_attrs(path, 1, &check))
 		return NULL;
 
 	if (ATTR_TRUE(check.value))
diff --git a/ws.c b/ws.c
index ea4b2b1..7350905 100644
--- a/ws.c
+++ b/ws.c
@@ -71,7 +71,7 @@ unsigned parse_whitespace_rule(const char *string)
 	return rule;
 }
 
-static void setup_whitespace_attr_check(struct git_attr_check *check)
+static void setup_whitespace_attr_check(struct git_attr_check_elem *check)
 {
 	static struct git_attr *attr_whitespace;
 
@@ -82,10 +82,10 @@ static void setup_whitespace_attr_check(struct git_attr_check *check)
 
 unsigned whitespace_rule(const char *pathname)
 {
-	struct git_attr_check attr_whitespace_rule;
+	struct git_attr_check_elem attr_whitespace_rule;
 
 	setup_whitespace_attr_check(&attr_whitespace_rule);
-	if (!git_check_attr(pathname, 1, &attr_whitespace_rule)) {
+	if (!git_check_attrs(pathname, 1, &attr_whitespace_rule)) {
 		const char *value;
 
 		value = attr_whitespace_rule.value;
-- 
2.10.1.469.g00a8914

[PATCH 11/35] attr: (re)introduce git_check_attr() and struct git_attr_check

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

A common pattern to check N attributes for many paths is to

 (1) prepare an array A of N git_attr_check_elem items;
 (2) call git_attr() to intern the N attribute names and fill A;
 (3) repeatedly call git_check_attrs() for path with N and A;

A look-up for these N attributes for a single path P scans the
entire attr_stack, starting from the .git/info/attributes file and
then .gitattributes file in the directory the path P is in, going
upwards to find .gitattributes file found in parent directories.

An earlier commit 06a604e6 (attr: avoid heavy work when we know the
specified attr is not defined, 2014-12-28) tried to optimize out
this scanning for one trivial special case: when the attribute being
sought is known not to exist, we do not have to scan for it.  While
this may be a cheap and effective heuristic, it would not work well
when N is (much) more than 1.

What we would want is a more customized way to skip irrelevant
entries in the attribute stack, and the definition of irrelevance
is tied to the set of attributes passed to git_check_attrs() call,
i.e. the set of attributes being sought.  The data necessary for
this optimization needs to live alongside the set of attributes, but
a simple array of git_attr_check_elem simply does not have any place
for that.

Introduce "struct git_attr_check" that contains N, the number of
attributes being sought, and A, the array that holds N
git_attr_check_elem items, and a function git_check_attr() that
takes a path P and this structure as its parameters.  This structure
can later be extended to hold extra data necessary for optimization.

Also, to make it easier to write the first two steps in common
cases, introduce git_attr_check_initl() helper function, which takes
a NULL-terminated list of attribute names and initialize this
structure.

As an illustration of this new API, convert archive.c that asks for
export-subst and export-ignore attributes for each paths.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 archive.c | 24 ++++++------------------
 attr.c    | 34 ++++++++++++++++++++++++++++++++++
 attr.h    |  9 +++++++++
 3 files changed, 49 insertions(+), 18 deletions(-)

diff --git a/archive.c b/archive.c
index 2dc8d6c..11e3951 100644
--- a/archive.c
+++ b/archive.c
@@ -87,19 +87,6 @@ void *sha1_file_to_archive(const struct archiver_args *args,
 	return buffer;
 }
 
-static void setup_archive_check(struct git_attr_check_elem *check)
-{
-	static struct git_attr *attr_export_ignore;
-	static struct git_attr *attr_export_subst;
-
-	if (!attr_export_ignore) {
-		attr_export_ignore = git_attr("export-ignore");
-		attr_export_subst = git_attr("export-subst");
-	}
-	check[0].attr = attr_export_ignore;
-	check[1].attr = attr_export_subst;
-}
-
 struct directory {
 	struct directory *up;
 	struct object_id oid;
@@ -123,7 +110,7 @@ static int write_archive_entry(const unsigned char *sha1, const char *base,
 	struct archiver_context *c = context;
 	struct archiver_args *args = c->args;
 	write_archive_entry_fn_t write_entry = c->write_entry;
-	struct git_attr_check_elem check[2];
+	static struct git_attr_check *check;
 	const char *path_without_prefix;
 	int err;
 
@@ -137,11 +124,12 @@ static int write_archive_entry(const unsigned char *sha1, const char *base,
 		strbuf_addch(&path, '/');
 	path_without_prefix = path.buf + args->baselen;
 
-	setup_archive_check(check);
-	if (!git_check_attrs(path_without_prefix, ARRAY_SIZE(check), check)) {
-		if (ATTR_TRUE(check[0].value))
+	if (!check)
+		check = git_attr_check_initl("export-ignore", "export-subst", NULL);
+	if (!git_check_attr(path_without_prefix, check)) {
+		if (ATTR_TRUE(check->check[0].value))
 			return 0;
-		args->convert = ATTR_TRUE(check[1].value);
+		args->convert = ATTR_TRUE(check->check[1].value);
 	}
 
 	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
diff --git a/attr.c b/attr.c
index c99e23a..861e1a2 100644
--- a/attr.c
+++ b/attr.c
@@ -829,3 +829,37 @@ void git_attr_set_direction(enum git_attr_direction new, struct index_state *ist
 		drop_attr_stack();
 	use_index = istate;
 }
+
+int git_check_attr(const char *path, struct git_attr_check *check)
+{
+	return git_check_attrs(path, check->check_nr, check->check);
+}
+
+struct git_attr_check *git_attr_check_initl(const char *one, ...)
+{
+	struct git_attr_check *check;
+	int cnt;
+	va_list params;
+	const char *param;
+
+	va_start(params, one);
+	for (cnt = 1; (param = va_arg(params, const char *)) != NULL; cnt++)
+		;
+	va_end(params);
+	check = xcalloc(1,
+			sizeof(*check) + cnt * sizeof(*(check->check)));
+	check->check_nr = cnt;
+	check->check = (struct git_attr_check_elem *)(check + 1);
+
+	check->check[0].attr = git_attr(one);
+	va_start(params, one);
+	for (cnt = 1; cnt < check->check_nr; cnt++) {
+		param = va_arg(params, const char *);
+		if (!param)
+			die("BUG: counted %d != ended at %d",
+			    check->check_nr, cnt);
+		check->check[cnt].attr = git_attr(param);
+	}
+	va_end(params);
+	return check;
+}
diff --git a/attr.h b/attr.h
index dd3c4a3..3fd8690 100644
--- a/attr.h
+++ b/attr.h
@@ -29,6 +29,15 @@ struct git_attr_check_elem {
 	const char *value;
 };
 
+struct git_attr_check {
+	int check_nr;
+	int check_alloc;
+	struct git_attr_check_elem *check;
+};
+
+extern struct git_attr_check *git_attr_check_initl(const char *, ...);
+extern int git_check_attr(const char *path, struct git_attr_check *);
+
 /*
  * Return the name of the attribute represented by the argument.  The
  * return value is a pointer to a null-delimited string that is part
-- 
2.10.1.469.g00a8914

[PATCH 12/35] attr: convert git_all_attrs() to use "struct git_attr_check"

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

This updates the other two ways the attribute check is done via an
array of "struct git_attr_check_elem" elements.  These two niches
appear only in "git check-attr".

 * The caller does not know offhand what attributes it wants to ask
   about and cannot use git_attr_check_initl() to prepare the
   git_attr_check structure.

 * The caller may not know what attributes it wants to ask at all,
   and instead wants to learn everything that the given path has.

Such a caller can call git_attr_check_alloc() to allocate an empty
git_attr_check, and then call git_attr_check_append() to add
attribute names one by one.  A new attribute can be appended until
git_attr_check structure is "finalized", which happens when it is
used to ask for attributes for any path by calling git_check_attr()
or git_all_attrs().  A git_attr_check structure that is initialized
by git_attr_check_initl() is already finalized when it is returned.

I am not at all happy with the way git_all_attrs() API turned out to
be, but it is only to support one niche caller ("check-attr --all"),
so I'll stop here for now.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c               | 75 ++++++++++++++++++++++++++++++++++++++--------------
 attr.h               | 16 ++++++-----
 builtin/check-attr.c | 51 ++++++++++++++++++-----------------
 3 files changed, 90 insertions(+), 52 deletions(-)

diff --git a/attr.c b/attr.c
index 861e1a2..76f0d6b 100644
--- a/attr.c
+++ b/attr.c
@@ -724,6 +724,11 @@ static int macroexpand_one(int nr, int rem)
 	return rem;
 }
 
+static int attr_check_is_dynamic(const struct git_attr_check *check)
+{
+	return (void *)(check->check) != (void *)(check + 1);
+}
+
 /*
  * Collect attributes for path into the array pointed to by
  * check_all_attr. If num is non-zero, only attributes in check[] are
@@ -789,32 +794,21 @@ int git_check_attrs(const char *path, int num, struct git_attr_check_elem *check
 	return 0;
 }
 
-int git_all_attrs(const char *path, int *num, struct git_attr_check_elem **check)
+void git_all_attrs(const char *path, struct git_attr_check *check)
 {
-	int i, count, j;
+	int i;
 
+	git_attr_check_clear(check);
 	collect_some_attrs(path, 0, NULL);
 
-	/* Count the number of attributes that are set. */
-	count = 0;
-	for (i = 0; i < attr_nr; i++) {
-		const char *value = check_all_attr[i].value;
-		if (value != ATTR__UNSET && value != ATTR__UNKNOWN)
-			++count;
-	}
-	*num = count;
-	ALLOC_ARRAY(*check, count);
-	j = 0;
 	for (i = 0; i < attr_nr; i++) {
+		const char *name = check_all_attr[i].attr->name;
 		const char *value = check_all_attr[i].value;
-		if (value != ATTR__UNSET && value != ATTR__UNKNOWN) {
-			(*check)[j].attr = check_all_attr[i].attr;
-			(*check)[j].value = value;
-			++j;
-		}
+		if (value == ATTR__UNSET || value == ATTR__UNKNOWN)
+			continue;
+		git_attr_check_append(check, git_attr(name));
+		check->check[check->check_nr - 1].value = value;
 	}
-
-	return 0;
 }
 
 void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
@@ -832,6 +826,7 @@ void git_attr_set_direction(enum git_attr_direction new, struct index_state *ist
 
 int git_check_attr(const char *path, struct git_attr_check *check)
 {
+	check->finalized = 1;
 	return git_check_attrs(path, check->check_nr, check->check);
 }
 
@@ -849,17 +844,57 @@ struct git_attr_check *git_attr_check_initl(const char *one, ...)
 	check = xcalloc(1,
 			sizeof(*check) + cnt * sizeof(*(check->check)));
 	check->check_nr = cnt;
+	check->finalized = 1;
 	check->check = (struct git_attr_check_elem *)(check + 1);
 
 	check->check[0].attr = git_attr(one);
 	va_start(params, one);
 	for (cnt = 1; cnt < check->check_nr; cnt++) {
+		struct git_attr *attr;
 		param = va_arg(params, const char *);
 		if (!param)
 			die("BUG: counted %d != ended at %d",
 			    check->check_nr, cnt);
-		check->check[cnt].attr = git_attr(param);
+		attr = git_attr(param);
+		if (!attr)
+			die("BUG: %s: not a valid attribute name", param);
+		check->check[cnt].attr = attr;
 	}
 	va_end(params);
 	return check;
 }
+
+struct git_attr_check *git_attr_check_alloc(void)
+{
+	return xcalloc(1, sizeof(struct git_attr_check));
+}
+
+struct git_attr_check_elem *git_attr_check_append(struct git_attr_check *check,
+						  const struct git_attr *attr)
+{
+	struct git_attr_check_elem *elem;
+	if (check->finalized)
+		die("BUG: append after git_attr_check structure is finalized");
+	if (!attr_check_is_dynamic(check))
+		die("BUG: appending to a statically initialized git_attr_check");
+	ALLOC_GROW(check->check, check->check_nr + 1, check->check_alloc);
+	elem = &check->check[check->check_nr++];
+	elem->attr = attr;
+	return elem;
+}
+
+void git_attr_check_clear(struct git_attr_check *check)
+{
+	if (!attr_check_is_dynamic(check))
+		die("BUG: clearing a statically initialized git_attr_check");
+	free(check->check);
+	check->check_nr = 0;
+	check->check_alloc = 0;
+	check->finalized = 0;
+}
+
+void git_attr_check_free(struct git_attr_check *check)
+{
+	git_attr_check_clear(check);
+	free(check);
+}
diff --git a/attr.h b/attr.h
index 3fd8690..0d94077 100644
--- a/attr.h
+++ b/attr.h
@@ -30,6 +30,7 @@ struct git_attr_check_elem {
 };
 
 struct git_attr_check {
+	int finalized;
 	int check_nr;
 	int check_alloc;
 	struct git_attr_check_elem *check;
@@ -38,6 +39,12 @@ struct git_attr_check {
 extern struct git_attr_check *git_attr_check_initl(const char *, ...);
 extern int git_check_attr(const char *path, struct git_attr_check *);
 
+extern struct git_attr_check *git_attr_check_alloc(void);
+extern struct git_attr_check_elem *git_attr_check_append(struct git_attr_check *, const struct git_attr *);
+
+extern void git_attr_check_clear(struct git_attr_check *);
+extern void git_attr_check_free(struct git_attr_check *);
+
 /*
  * Return the name of the attribute represented by the argument.  The
  * return value is a pointer to a null-delimited string that is part
@@ -48,13 +55,10 @@ extern const char *git_attr_name(const struct git_attr *);
 int git_check_attrs(const char *path, int, struct git_attr_check_elem *);
 
 /*
- * Retrieve all attributes that apply to the specified path.  *num
- * will be set to the number of attributes on the path; **check will
- * be set to point at a newly-allocated array of git_attr_check
- * objects describing the attributes and their values.  *check must be
- * free()ed by the caller.
+ * Retrieve all attributes that apply to the specified path.
+ * check holds the attributes and their values.
  */
-int git_all_attrs(const char *path, int *num, struct git_attr_check_elem **check);
+void git_all_attrs(const char *path, struct git_attr_check *check);
 
 enum git_attr_direction {
 	GIT_ATTR_CHECKIN,
diff --git a/builtin/check-attr.c b/builtin/check-attr.c
index 97e3837..ec61476 100644
--- a/builtin/check-attr.c
+++ b/builtin/check-attr.c
@@ -24,12 +24,13 @@ static const struct option check_attr_options[] = {
 	OPT_END()
 };
 
-static void output_attr(int cnt, struct git_attr_check_elem *check,
-			const char *file)
+static void output_attr(struct git_attr_check *check, const char *file)
 {
 	int j;
+	int cnt = check->check_nr;
+
 	for (j = 0; j < cnt; j++) {
-		const char *value = check[j].value;
+		const char *value = check->check[j].value;
 
 		if (ATTR_TRUE(value))
 			value = "set";
@@ -42,36 +43,37 @@ static void output_attr(int cnt, struct git_attr_check_elem *check,
 			printf("%s%c" /* path */
 			       "%s%c" /* attrname */
 			       "%s%c" /* attrvalue */,
-			       file, 0, git_attr_name(check[j].attr), 0, value, 0);
+			       file, 0,
+			       git_attr_name(check->check[j].attr), 0, value, 0);
 		} else {
 			quote_c_style(file, NULL, stdout, 0);
-			printf(": %s: %s\n", git_attr_name(check[j].attr), value);
+			printf(": %s: %s\n",
+			       git_attr_name(check->check[j].attr), value);
 		}
-
 	}
 }
 
 static void check_attr(const char *prefix,
-		       int cnt, struct git_attr_check_elem *check,
+		       struct git_attr_check *check,
 		       const char *file)
 {
 	char *full_path =
 		prefix_path(prefix, prefix ? strlen(prefix) : 0, file);
 	if (check != NULL) {
-		if (git_check_attrs(full_path, cnt, check))
-			die("git_check_attrs died");
-		output_attr(cnt, check, file);
+		if (git_check_attr(full_path, check))
+			die("git_check_attr died");
+		output_attr(check, file);
 	} else {
-		if (git_all_attrs(full_path, &cnt, &check))
-			die("git_all_attrs died");
-		output_attr(cnt, check, file);
-		free(check);
+		check = git_attr_check_alloc();
+		git_all_attrs(full_path, check);
+		output_attr(check, file);
+		git_attr_check_free(check);
 	}
 	free(full_path);
 }
 
 static void check_attr_stdin_paths(const char *prefix,
-				   int cnt, struct git_attr_check_elem *check)
+				   struct git_attr_check *check)
 {
 	struct strbuf buf = STRBUF_INIT;
 	struct strbuf unquoted = STRBUF_INIT;
@@ -85,7 +87,7 @@ static void check_attr_stdin_paths(const char *prefix,
 				die("line is badly quoted");
 			strbuf_swap(&buf, &unquoted);
 		}
-		check_attr(prefix, cnt, check, buf.buf);
+		check_attr(prefix, check, buf.buf);
 		maybe_flush_or_die(stdout, "attribute to stdout");
 	}
 	strbuf_release(&buf);
@@ -100,7 +102,7 @@ static NORETURN void error_with_usage(const char *msg)
 
 int cmd_check_attr(int argc, const char **argv, const char *prefix)
 {
-	struct git_attr_check_elem *check;
+	struct git_attr_check *check;
 	int cnt, i, doubledash, filei;
 
 	if (!is_bare_repository())
@@ -163,24 +165,21 @@ int cmd_check_attr(int argc, const char **argv, const char *prefix)
 	if (all_attrs) {
 		check = NULL;
 	} else {
-		check = xcalloc(cnt, sizeof(*check));
+		check = git_attr_check_alloc();
 		for (i = 0; i < cnt; i++) {
-			const char *name;
-			struct git_attr *a;
-			name = argv[i];
-			a = git_attr(name);
+			struct git_attr *a = git_attr(argv[i]);
 			if (!a)
 				return error("%s: not a valid attribute name",
-					name);
-			check[i].attr = a;
+					     argv[i]);
+			git_attr_check_append(check, a);
 		}
 	}
 
 	if (stdin_paths)
-		check_attr_stdin_paths(prefix, cnt, check);
+		check_attr_stdin_paths(prefix, check);
 	else {
 		for (i = filei; i < argc; i++)
-			check_attr(prefix, cnt, check, argv[i]);
+			check_attr(prefix, check, argv[i]);
 		maybe_flush_or_die(stdout, "attribute to stdout");
 	}
 	return 0;
-- 
2.10.1.469.g00a8914

[PATCH 13/35] attr: convert git_check_attrs() callers to use the new API

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

The remaining callers are all simple "I have N attributes I am
interested in.  I'll ask about them with various paths one by one".

After this step, no caller to git_check_attrs() remains.  After
removing it, we can extend "struct git_attr_check" struct with data
that can be used in optimizing the query for the specific N
attributes it contains.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/pack-objects.c | 19 +++++--------------
 convert.c              | 18 +++++++-----------
 ll-merge.c             | 33 ++++++++++++++-------------------
 userdiff.c             | 19 ++++++++-----------
 ws.c                   | 19 ++++++-------------
 5 files changed, 40 insertions(+), 68 deletions(-)

diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 3cb38ed..3918c07 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -896,24 +896,15 @@ static void write_pack_file(void)
 			written, nr_result);
 }
 
-static void setup_delta_attr_check(struct git_attr_check_elem *check)
-{
-	static struct git_attr *attr_delta;
-
-	if (!attr_delta)
-		attr_delta = git_attr("delta");
-
-	check[0].attr = attr_delta;
-}
-
 static int no_try_delta(const char *path)
 {
-	struct git_attr_check_elem check[1];
+	static struct git_attr_check *check;
 
-	setup_delta_attr_check(check);
-	if (git_check_attrs(path, ARRAY_SIZE(check), check))
+	if (!check)
+		check = git_attr_check_initl("delta", NULL);
+	if (git_check_attr(path, check))
 		return 0;
-	if (ATTR_FALSE(check->value))
+	if (ATTR_FALSE(check->check[0].value))
 		return 1;
 	return 0;
 }
diff --git a/convert.c b/convert.c
index c95ae71..bb2435a 100644
--- a/convert.c
+++ b/convert.c
@@ -775,24 +775,20 @@ struct conv_attrs {
 	int ident;
 };
 
-static const char *conv_attr_name[] = {
-	"crlf", "ident", "filter", "eol", "text",
-};
-#define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
-
 static void convert_attrs(struct conv_attrs *ca, const char *path)
 {
-	int i;
-	static struct git_attr_check_elem ccheck[NUM_CONV_ATTRS];
+	static struct git_attr_check *check;
 
-	if (!ccheck[0].attr) {
-		for (i = 0; i < NUM_CONV_ATTRS; i++)
-			ccheck[i].attr = git_attr(conv_attr_name[i]);
+	if (!check) {
+		check = git_attr_check_initl("crlf", "ident",
+					     "filter", "eol", "text",
+					     NULL);
 		user_convert_tail = &user_convert;
 		git_config(read_convert_config, NULL);
 	}
 
-	if (!git_check_attrs(path, NUM_CONV_ATTRS, ccheck)) {
+	if (!git_check_attr(path, check)) {
+		struct git_attr_check_elem *ccheck = check->check;
 		ca->crlf_action = git_path_check_crlf(ccheck + 4);
 		if (ca->crlf_action == CRLF_UNDEFINED)
 			ca->crlf_action = git_path_check_crlf(ccheck + 0);
diff --git a/ll-merge.c b/ll-merge.c
index eb2c37e..bc6479c 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -336,15 +336,6 @@ static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr
 	return &ll_merge_drv[LL_TEXT_MERGE];
 }
 
-static int git_path_check_merge(const char *path, struct git_attr_check_elem check[2])
-{
-	if (!check[0].attr) {
-		check[0].attr = git_attr("merge");
-		check[1].attr = git_attr("conflict-marker-size");
-	}
-	return git_check_attrs(path, 2, check);
-}
-
 static void normalize_file(mmfile_t *mm, const char *path)
 {
 	struct strbuf strbuf = STRBUF_INIT;
@@ -362,7 +353,7 @@ int ll_merge(mmbuffer_t *result_buf,
 	     mmfile_t *theirs, const char *their_label,
 	     const struct ll_merge_options *opts)
 {
-	static struct git_attr_check_elem check[2];
+	static struct git_attr_check *check;
 	static const struct ll_merge_options default_opts;
 	const char *ll_driver_name = NULL;
 	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
@@ -376,10 +367,14 @@ int ll_merge(mmbuffer_t *result_buf,
 		normalize_file(ours, path);
 		normalize_file(theirs, path);
 	}
-	if (!git_path_check_merge(path, check)) {
-		ll_driver_name = check[0].value;
-		if (check[1].value) {
-			marker_size = atoi(check[1].value);
+
+	if (!check)
+		check = git_attr_check_initl("merge", "conflict-marker-size", NULL);
+
+	if (!git_check_attr(path, check)) {
+		ll_driver_name = check->check[0].value;
+		if (check->check[1].value) {
+			marker_size = atoi(check->check[1].value);
 			if (marker_size <= 0)
 				marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 		}
@@ -398,13 +393,13 @@ int ll_merge(mmbuffer_t *result_buf,
 
 int ll_merge_marker_size(const char *path)
 {
-	static struct git_attr_check_elem check;
+	static struct git_attr_check *check;
 	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 
-	if (!check.attr)
-		check.attr = git_attr("conflict-marker-size");
-	if (!git_check_attrs(path, 1, &check) && check.value) {
-		marker_size = atoi(check.value);
+	if (!check)
+		check = git_attr_check_initl("conflict-marker-size", NULL);
+	if (!git_check_attr(path, check) && check->check[0].value) {
+		marker_size = atoi(check->check[0].value);
 		if (marker_size <= 0)
 			marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 	}
diff --git a/userdiff.c b/userdiff.c
index 4de3289..46dfd32 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -262,25 +262,22 @@ struct userdiff_driver *userdiff_find_by_name(const char *name) {
 
 struct userdiff_driver *userdiff_find_by_path(const char *path)
 {
-	static struct git_attr *attr;
-	struct git_attr_check_elem check;
-
-	if (!attr)
-		attr = git_attr("diff");
-	check.attr = attr;
+	static struct git_attr_check *check;
 
+	if (!check)
+		check = git_attr_check_initl("diff", NULL);
 	if (!path)
 		return NULL;
-	if (git_check_attrs(path, 1, &check))
+	if (git_check_attr(path, check))
 		return NULL;
 
-	if (ATTR_TRUE(check.value))
+	if (ATTR_TRUE(check->check[0].value))
 		return &driver_true;
-	if (ATTR_FALSE(check.value))
+	if (ATTR_FALSE(check->check[0].value))
 		return &driver_false;
-	if (ATTR_UNSET(check.value))
+	if (ATTR_UNSET(check->check[0].value))
 		return NULL;
-	return userdiff_find_by_name(check.value);
+	return userdiff_find_by_name(check->check[0].value);
 }
 
 struct userdiff_driver *userdiff_get_textconv(struct userdiff_driver *driver)
diff --git a/ws.c b/ws.c
index 7350905..bb3270c 100644
--- a/ws.c
+++ b/ws.c
@@ -71,24 +71,17 @@ unsigned parse_whitespace_rule(const char *string)
 	return rule;
 }
 
-static void setup_whitespace_attr_check(struct git_attr_check_elem *check)
-{
-	static struct git_attr *attr_whitespace;
-
-	if (!attr_whitespace)
-		attr_whitespace = git_attr("whitespace");
-	check[0].attr = attr_whitespace;
-}
-
 unsigned whitespace_rule(const char *pathname)
 {
-	struct git_attr_check_elem attr_whitespace_rule;
+	static struct git_attr_check *attr_whitespace_rule;
+
+	if (!attr_whitespace_rule)
+		attr_whitespace_rule = git_attr_check_initl("whitespace", NULL);
 
-	setup_whitespace_attr_check(&attr_whitespace_rule);
-	if (!git_check_attrs(pathname, 1, &attr_whitespace_rule)) {
+	if (!git_check_attr(pathname, attr_whitespace_rule)) {
 		const char *value;
 
-		value = attr_whitespace_rule.value;
+		value = attr_whitespace_rule->check[0].value;
 		if (ATTR_TRUE(value)) {
 			/* true (whitespace) */
 			unsigned all_rule = ws_tab_width(whitespace_rule_cfg);
-- 
2.10.1.469.g00a8914

[PATCH 14/35] attr: retire git_check_attrs() API

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Since nobody uses the old API, make it file-scope static, and update
the documentation to describe the new API.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/technical/api-gitattributes.txt | 82 ++++++++++++++++++---------
 attr.c                                        |  3 +-
 attr.h                                        |  2 -
 3 files changed, 56 insertions(+), 31 deletions(-)

diff --git a/Documentation/technical/api-gitattributes.txt b/Documentation/technical/api-gitattributes.txt
index 2602668..92fc32a 100644
--- a/Documentation/technical/api-gitattributes.txt
+++ b/Documentation/technical/api-gitattributes.txt
@@ -16,10 +16,15 @@ Data Structure
 	of no interest to the calling programs.  The name of the
 	attribute can be retrieved by calling `git_attr_name()`.
 
+`struct git_attr_check_elem`::
+
+	This structure represents one attribute and its value.
+
 `struct git_attr_check`::
 
-	This structure represents a set of attributes to check in a call
-	to `git_check_attr()` function, and receives the results.
+	This structure represents a collection of `git_attr_check_elem`.
+	It is passed to `git_check_attr()` function, specifying the
+	attributes to check, and receives their values.
 
 
 Attribute Values
@@ -48,49 +53,51 @@ value of the attribute for the path.
 Querying Specific Attributes
 ----------------------------
 
-* Prepare an array of `struct git_attr_check` to define the list of
-  attributes you would want to check.  To populate this array, you would
-  need to define necessary attributes by calling `git_attr()` function.
+* Prepare `struct git_attr_check` using git_attr_check_initl()
+  function, enumerating the names of attributes whose values you are
+  interested in, terminated with a NULL pointer.  Alternatively, an
+  empty `struct git_attr_check` can be prepared by calling
+  `git_attr_check_alloc()` function and then attributes you want to
+  ask about can be added to it with `git_attr_check_append()`
+  function.
 
 * Call `git_check_attr()` to check the attributes for the path.
 
-* Inspect `git_attr_check` structure to see how each of the attribute in
-  the array is defined for the path.
+* Inspect `git_attr_check` structure to see how each of the
+  attribute in the array is defined for the path.
 
 
 Example
 -------
 
-To see how attributes "crlf" and "indent" are set for different paths.
+To see how attributes "crlf" and "ident" are set for different paths.
 
-. Prepare an array of `struct git_attr_check` with two elements (because
-  we are checking two attributes).  Initialize their `attr` member with
-  pointers to `struct git_attr` obtained by calling `git_attr()`:
+. Prepare a `struct git_attr_check` with two elements (because
+  we are checking two attributes):
 
 ------------
-static struct git_attr_check check[2];
+static struct git_attr_check *check;
 static void setup_check(void)
 {
-	if (check[0].attr)
+	if (check)
 		return; /* already done */
-	check[0].attr = git_attr("crlf");
-	check[1].attr = git_attr("ident");
+	check = git_attr_check_initl("crlf", "ident", NULL);
 }
 ------------
 
-. Call `git_check_attr()` with the prepared array of `struct git_attr_check`:
+. Call `git_check_attr()` with the prepared `struct git_attr_check`:
 
 ------------
 	const char *path;
 
 	setup_check();
-	git_check_attr(path, ARRAY_SIZE(check), check);
+	git_check_attr(path, check);
 ------------
 
-. Act on `.value` member of the result, left in `check[]`:
+. Act on `.value` member of the result, left in `check->check[]`:
 
 ------------
-	const char *value = check[0].value;
+	const char *value = check->check[0].value;
 
 	if (ATTR_TRUE(value)) {
 		The attribute is Set, by listing only the name of the
@@ -109,20 +116,39 @@ static void setup_check(void)
 	}
 ------------
 
+To see how attributes in argv[] are set for different paths, only
+the first step in the above would be different.
+
+------------
+static struct git_attr_check *check;
+static void setup_check(const char **argv)
+{
+	check = git_attr_check_alloc();
+	while (*argv) {
+		struct git_attr *attr = git_attr(*argv);
+		git_attr_check_append(check, attr);
+		argv++;
+	}
+}
+------------
+
 
 Querying All Attributes
 -----------------------
 
 To get the values of all attributes associated with a file:
 
-* Call `git_all_attrs()`, which returns an array of `git_attr_check`
-  structures.
+* Prepare an empty `git_attr_check` structure by calling
+  `git_attr_check_alloc()`.
+
+* Call `git_all_attrs()`, which populates the `git_attr_check`
+  with the attributes attached to the path.
 
-* Iterate over the `git_attr_check` array to examine the attribute
-  names and values.  The name of the attribute described by a
-  `git_attr_check` object can be retrieved via
-  `git_attr_name(check[i].attr)`.  (Please note that no items will be
-  returned for unset attributes, so `ATTR_UNSET()` will return false
-  for all returned `git_array_check` objects.)
+* Iterate over the `git_attr_check.check[]` array to examine
+  the attribute names and values.  The name of the attribute
+  described by a  `git_attr_check.check[]` object can be retrieved via
+  `git_attr_name(check->check[i].attr)`.  (Please note that no items
+  will be returned for unset attributes, so `ATTR_UNSET()` will return
+  false for all returned `git_array_check` objects.)
 
-* Free the `git_array_check` array.
+* Free the `git_array_check` by calling `git_attr_check_free()`.
diff --git a/attr.c b/attr.c
index 76f0d6b..d427798 100644
--- a/attr.c
+++ b/attr.c
@@ -778,7 +778,8 @@ static void collect_some_attrs(const char *path, int num,
 		rem = fill(path, pathlen, basename_offset, stk, rem);
 }
 
-int git_check_attrs(const char *path, int num, struct git_attr_check_elem *check)
+static int git_check_attrs(const char *path, int num,
+			   struct git_attr_check_elem *check)
 {
 	int i;
 
diff --git a/attr.h b/attr.h
index 0d94077..506db0c 100644
--- a/attr.h
+++ b/attr.h
@@ -52,8 +52,6 @@ extern void git_attr_check_free(struct git_attr_check *);
  */
 extern const char *git_attr_name(const struct git_attr *);
 
-int git_check_attrs(const char *path, int, struct git_attr_check_elem *);
-
 /*
  * Retrieve all attributes that apply to the specified path.
  * check holds the attributes and their values.
-- 
2.10.1.469.g00a8914

[PATCH 15/35] attr: add counted string version of git_check_attr()

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Often a potential caller has <path, pathlen> pair that
represents the path it wants to ask attributes for; when
path[pathlen] is not NUL, the caller has to xmemdupz()
only to call git_check_attr().

Add git_check_attr_counted() that takes such a counted
string instead of "const char *path".

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 23 ++++++++++++++---------
 attr.h |  1 +
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/attr.c b/attr.c
index d427798..9bec243 100644
--- a/attr.c
+++ b/attr.c
@@ -734,20 +734,19 @@ static int attr_check_is_dynamic(const struct git_attr_check *check)
  * check_all_attr. If num is non-zero, only attributes in check[] are
  * collected. Otherwise all attributes are collected.
  */
-static void collect_some_attrs(const char *path, int num,
+static void collect_some_attrs(const char *path, int pathlen, int num,
 			       struct git_attr_check_elem *check)
 
 {
 	struct attr_stack *stk;
-	int i, pathlen, rem, dirlen;
+	int i, rem, dirlen;
 	const char *cp, *last_slash = NULL;
 	int basename_offset;
 
-	for (cp = path; *cp; cp++) {
+	for (cp = path; cp < path + pathlen; cp++) {
 		if (*cp == '/' && cp[1])
 			last_slash = cp;
 	}
-	pathlen = cp - path;
 	if (last_slash) {
 		basename_offset = last_slash + 1 - path;
 		dirlen = last_slash - path;
@@ -778,12 +777,12 @@ static void collect_some_attrs(const char *path, int num,
 		rem = fill(path, pathlen, basename_offset, stk, rem);
 }
 
-static int git_check_attrs(const char *path, int num,
+static int git_check_attrs(const char *path, int pathlen, int num,
 			   struct git_attr_check_elem *check)
 {
 	int i;
 
-	collect_some_attrs(path, num, check);
+	collect_some_attrs(path, pathlen, num, check);
 
 	for (i = 0; i < num; i++) {
 		const char *value = check_all_attr[check[i].attr->attr_nr].value;
@@ -800,7 +799,7 @@ void git_all_attrs(const char *path, struct git_attr_check *check)
 	int i;
 
 	git_attr_check_clear(check);
-	collect_some_attrs(path, 0, NULL);
+	collect_some_attrs(path, strlen(path), 0, NULL);
 
 	for (i = 0; i < attr_nr; i++) {
 		const char *name = check_all_attr[i].attr->name;
@@ -825,10 +824,16 @@ void git_attr_set_direction(enum git_attr_direction new, struct index_state *ist
 	use_index = istate;
 }
 
-int git_check_attr(const char *path, struct git_attr_check *check)
+int git_check_attr_counted(const char *path, int pathlen,
+			   struct git_attr_check *check)
 {
 	check->finalized = 1;
-	return git_check_attrs(path, check->check_nr, check->check);
+	return git_check_attrs(path, pathlen, check->check_nr, check->check);
+}
+
+int git_check_attr(const char *path, struct git_attr_check *check)
+{
+	return git_check_attr_counted(path, strlen(path), check);
 }
 
 struct git_attr_check *git_attr_check_initl(const char *one, ...)
diff --git a/attr.h b/attr.h
index 506db0c..c84f164 100644
--- a/attr.h
+++ b/attr.h
@@ -38,6 +38,7 @@ struct git_attr_check {
 
 extern struct git_attr_check *git_attr_check_initl(const char *, ...);
 extern int git_check_attr(const char *path, struct git_attr_check *);
+extern int git_check_attr_counted(const char *, int, struct git_attr_check *);
 
 extern struct git_attr_check *git_attr_check_alloc(void);
 extern struct git_attr_check_elem *git_attr_check_append(struct git_attr_check *, const struct git_attr *);
-- 
2.10.1.469.g00a8914

[PATCH 16/35] attr: expose validity check for attribute names

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Export attr_name_valid() function, and a helper function that
returns the message to be given when a given <name, len> pair
is not a good name for an attribute.

We could later update the message to exactly spell out what the
rules for a good attribute name are, etc.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 39 +++++++++++++++++++++++++--------------
 attr.h | 10 ++++++++++
 2 files changed, 35 insertions(+), 14 deletions(-)

diff --git a/attr.c b/attr.c
index 9bec243..14bbfd4 100644
--- a/attr.c
+++ b/attr.c
@@ -59,23 +59,38 @@ static unsigned hash_name(const char *name, int namelen)
 	return val;
 }
 
-static int invalid_attr_name(const char *name, int namelen)
+int attr_name_valid(const char *name, size_t namelen)
 {
 	/*
 	 * Attribute name cannot begin with '-' and must consist of
 	 * characters from [-A-Za-z0-9_.].
 	 */
 	if (namelen <= 0 || *name == '-')
-		return -1;
+		return 0;
 	while (namelen--) {
 		char ch = *name++;
 		if (! (ch == '-' || ch == '.' || ch == '_' ||
 		       ('0' <= ch && ch <= '9') ||
 		       ('a' <= ch && ch <= 'z') ||
 		       ('A' <= ch && ch <= 'Z')) )
-			return -1;
+			return 0;
 	}
-	return 0;
+	return 1;
+}
+
+void invalid_attr_name_message(struct strbuf *err, const char *name, int len)
+{
+	strbuf_addf(err, _("%.*s is not a valid attribute name"),
+		    len, name);
+}
+
+static void report_invalid_attr(const char *name, size_t len,
+				const char *src, int lineno)
+{
+	struct strbuf err = STRBUF_INIT;
+	invalid_attr_name_message(&err, name, len);
+	fprintf(stderr, "%s: %s:%d\n", err.buf, src, lineno);
+	strbuf_release(&err);
 }
 
 static struct git_attr *git_attr_internal(const char *name, int len)
@@ -90,7 +105,7 @@ static struct git_attr *git_attr_internal(const char *name, int len)
 			return a;
 	}
 
-	if (invalid_attr_name(name, len))
+	if (!attr_name_valid(name, len))
 		return NULL;
 
 	FLEX_ALLOC_MEM(a, name, name, len);
@@ -176,17 +191,15 @@ static const char *parse_attr(const char *src, int lineno, const char *cp,
 			cp++;
 			len--;
 		}
-		if (invalid_attr_name(cp, len)) {
-			fprintf(stderr,
-				"%.*s is not a valid attribute name: %s:%d\n",
-				len, cp, src, lineno);
+		if (!attr_name_valid(cp, len)) {
+			report_invalid_attr(cp, len, src, lineno);
 			return NULL;
 		}
 	} else {
 		/*
 		 * As this function is always called twice, once with
 		 * e == NULL in the first pass and then e != NULL in
-		 * the second pass, no need for invalid_attr_name()
+		 * the second pass, no need for attr_name_valid()
 		 * check here.
 		 */
 		if (*cp == '-' || *cp == '!') {
@@ -229,10 +242,8 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 		name += strlen(ATTRIBUTE_MACRO_PREFIX);
 		name += strspn(name, blank);
 		namelen = strcspn(name, blank);
-		if (invalid_attr_name(name, namelen)) {
-			fprintf(stderr,
-				"%.*s is not a valid attribute name: %s:%d\n",
-				namelen, name, src, lineno);
+		if (!attr_name_valid(name, namelen)) {
+			report_invalid_attr(name, namelen, src, lineno);
 			goto fail_return;
 		}
 	}
diff --git a/attr.h b/attr.h
index c84f164..1c6a6d8 100644
--- a/attr.h
+++ b/attr.h
@@ -10,6 +10,16 @@ struct git_attr;
  */
 struct git_attr *git_attr(const char *);
 
+/*
+ * Return the name of the attribute represented by the argument.  The
+ * return value is a pointer to a null-delimited string that is part
+ * of the internal data structure; it should not be modified or freed.
+ */
+extern const char *git_attr_name(const struct git_attr *);
+
+extern int attr_name_valid(const char *name, size_t namelen);
+extern void invalid_attr_name_message(struct strbuf *, const char *, int);
+
 /* Internal use */
 extern const char git_attr__true[];
 extern const char git_attr__false[];
-- 
2.10.1.469.g00a8914

[PATCH 17/35] attr: support quoting pathname patterns in C style

[Stefan Beller]

From: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>

Full pattern must be quoted. So 'pat"t"ern attr' will give exactly
'pat"t"ern', not 'pattern'. Also clarify that leading whitespaces are
not part of the pattern and document comment syntax.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/gitattributes.txt |  8 +++++---
 attr.c                          | 15 +++++++++++++--
 t/t0003-attributes.sh           | 26 ++++++++++++++++++++++++++
 3 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 7aff940..8a061af 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -21,9 +21,11 @@ Each line in `gitattributes` file is of form:
 	pattern	attr1 attr2 ...
 
 That is, a pattern followed by an attributes list,
-separated by whitespaces.  When the pattern matches the
-path in question, the attributes listed on the line are given to
-the path.
+separated by whitespaces. Leading and trailing whitespaces are
+ignored. Lines that begin with '#' are ignored. Patterns
+that begin with a double quote are quoted in C style.
+When the pattern matches the path in question, the attributes
+listed on the line are given to the path.
 
 Each attribute can be in one of these states for a given path:
 
diff --git a/attr.c b/attr.c
index 14bbfd4..88fcb7c 100644
--- a/attr.c
+++ b/attr.c
@@ -13,6 +13,7 @@
 #include "attr.h"
 #include "dir.h"
 #include "utf8.h"
+#include "quote.h"
 
 const char git_attr__true[] = "(builtin)true";
 const char git_attr__false[] = "\0(builtin)false";
@@ -225,12 +226,21 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 	const char *cp, *name, *states;
 	struct match_attr *res = NULL;
 	int is_macro;
+	struct strbuf pattern = STRBUF_INIT;
 
 	cp = line + strspn(line, blank);
 	if (!*cp || *cp == '#')
 		return NULL;
 	name = cp;
-	namelen = strcspn(name, blank);
+
+	if (*cp == '"' && !unquote_c_style(&pattern, name, &states)) {
+		name = pattern.buf;
+		namelen = pattern.len;
+	} else {
+		namelen = strcspn(name, blank);
+		states = name + namelen;
+	}
+
 	if (strlen(ATTRIBUTE_MACRO_PREFIX) < namelen &&
 	    starts_with(name, ATTRIBUTE_MACRO_PREFIX)) {
 		if (!macro_ok) {
@@ -250,7 +260,6 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 	else
 		is_macro = 0;
 
-	states = name + namelen;
 	states += strspn(states, blank);
 
 	/* First pass to count the attr_states */
@@ -293,9 +302,11 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
 			cannot_trust_maybe_real = 1;
 	}
 
+	strbuf_release(&pattern);
 	return res;
 
 fail_return:
+	strbuf_release(&pattern);
 	free(res);
 	return NULL;
 }
diff --git a/t/t0003-attributes.sh b/t/t0003-attributes.sh
index f0fbb42..f19ae4f 100755
--- a/t/t0003-attributes.sh
+++ b/t/t0003-attributes.sh
@@ -13,10 +13,31 @@ attr_check () {
 	test_line_count = 0 err
 }
 
+attr_check_quote () {
+
+	path="$1"
+	quoted_path="$2"
+	expect="$3"
+
+	git check-attr test -- "$path" >actual &&
+	echo "\"$quoted_path\": test: $expect" >expect &&
+	test_cmp expect actual
+
+}
+
+test_expect_success 'open-quoted pathname' '
+	echo "\"a test=a" >.gitattributes &&
+	test_must_fail attr_check a a
+'
+
+
 test_expect_success 'setup' '
 	mkdir -p a/b/d a/c b &&
 	(
 		echo "[attr]notest !test"
+		echo "\" d \"	test=d"
+		echo " e	test=e"
+		echo " e\"	test=e"
 		echo "f	test=f"
 		echo "a/i test=a/i"
 		echo "onoff test -test"
@@ -69,6 +90,11 @@ test_expect_success 'command line checks' '
 '
 
 test_expect_success 'attribute test' '
+
+	attr_check " d " d &&
+	attr_check e e &&
+	attr_check_quote e\" e\\\" e &&
+
 	attr_check f f &&
 	attr_check a/f f &&
 	attr_check a/c/f f &&
-- 
2.10.1.469.g00a8914

[PATCH 18/35] attr.c: add push_stack() helper

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

There are too many repetitious "I have this new attr_stack element;
push it at the top of the stack" sequence.  The new helper function
push_stack() gives us a way to express what is going on at these
places, and as a side effect, halves the number of times we mention
the attr_stack global variable.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 71 +++++++++++++++++++++++++++++++-----------------------------------
 1 file changed, 33 insertions(+), 38 deletions(-)

diff --git a/attr.c b/attr.c
index 88fcb7c..a504cb3 100644
--- a/attr.c
+++ b/attr.c
@@ -521,6 +521,18 @@ static int git_attr_system(void)
 
 static GIT_PATH_FUNC(git_path_info_attributes, INFOATTRIBUTES_FILE)
 
+static void push_stack(struct attr_stack **attr_stack_p,
+		       struct attr_stack *elem, char *origin, size_t originlen)
+{
+	if (elem) {
+		elem->origin = origin;
+		if (origin)
+			elem->originlen = originlen;
+		elem->prev = *attr_stack_p;
+		*attr_stack_p = elem;
+	}
+}
+
 static void bootstrap_attr_stack(void)
 {
 	struct attr_stack *elem;
@@ -528,52 +540,35 @@ static void bootstrap_attr_stack(void)
 	if (attr_stack)
 		return;
 
-	elem = read_attr_from_array(builtin_attr);
-	elem->origin = NULL;
-	elem->prev = attr_stack;
-	attr_stack = elem;
-
-	if (git_attr_system()) {
-		elem = read_attr_from_file(git_etc_gitattributes(), 1);
-		if (elem) {
-			elem->origin = NULL;
-			elem->prev = attr_stack;
-			attr_stack = elem;
-		}
-	}
+	push_stack(&attr_stack, read_attr_from_array(builtin_attr), NULL, 0);
+
+	if (git_attr_system())
+		push_stack(&attr_stack,
+			   read_attr_from_file(git_etc_gitattributes(), 1),
+			   NULL, 0);
 
 	if (!git_attributes_file)
 		git_attributes_file = xdg_config_home("attributes");
-	if (git_attributes_file) {
-		elem = read_attr_from_file(git_attributes_file, 1);
-		if (elem) {
-			elem->origin = NULL;
-			elem->prev = attr_stack;
-			attr_stack = elem;
-		}
-	}
+	if (git_attributes_file)
+		push_stack(&attr_stack,
+			   read_attr_from_file(git_attributes_file, 1),
+			   NULL, 0);
 
 	if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
 		elem = read_attr(GITATTRIBUTES_FILE, 1);
-		elem->origin = xstrdup("");
-		elem->originlen = 0;
-		elem->prev = attr_stack;
-		attr_stack = elem;
+		push_stack(&attr_stack, elem, xstrdup(""), 0);
 		debug_push(elem);
 	}
 
 	elem = read_attr_from_file(git_path_info_attributes(), 1);
 	if (!elem)
 		elem = xcalloc(1, sizeof(*elem));
-	elem->origin = NULL;
-	elem->prev = attr_stack;
-	attr_stack = elem;
+	push_stack(&attr_stack, elem, NULL, 0);
 }
 
 static void prepare_attr_stack(const char *path, int dirlen)
 {
 	struct attr_stack *elem, *info;
-	int len;
 	const char *cp;
 
 	/*
@@ -633,20 +628,21 @@ static void prepare_attr_stack(const char *path, int dirlen)
 
 		assert(attr_stack->origin);
 		while (1) {
-			len = strlen(attr_stack->origin);
+			size_t len = strlen(attr_stack->origin);
+			char *origin;
+
 			if (dirlen <= len)
 				break;
 			cp = memchr(path + len + 1, '/', dirlen - len - 1);
 			if (!cp)
 				cp = path + dirlen;
-			strbuf_add(&pathbuf, path, cp - path);
-			strbuf_addch(&pathbuf, '/');
-			strbuf_addstr(&pathbuf, GITATTRIBUTES_FILE);
+			strbuf_addf(&pathbuf,
+				    "%.*s/%s", (int)(cp - path), path,
+				    GITATTRIBUTES_FILE);
 			elem = read_attr(pathbuf.buf, 0);
 			strbuf_setlen(&pathbuf, cp - path);
-			elem->origin = strbuf_detach(&pathbuf, &elem->originlen);
-			elem->prev = attr_stack;
-			attr_stack = elem;
+			origin = strbuf_detach(&pathbuf, &len);
+			push_stack(&attr_stack, elem, origin, len);
 			debug_push(elem);
 		}
 
@@ -656,8 +652,7 @@ static void prepare_attr_stack(const char *path, int dirlen)
 	/*
 	 * Finally push the "info" one at the top of the stack.
 	 */
-	info->prev = attr_stack;
-	attr_stack = info;
+	push_stack(&attr_stack, info, NULL, 0);
 }
 
 static int path_matches(const char *pathname, int pathlen,
-- 
2.10.1.469.g00a8914

[PATCH 19/35] attr.c: pass struct git_attr_check down the callchain

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

The callchain that starts from git_check_attrs() down to
collect_some_attrs() used to take an array of git_attr_check_elem
as their parameters.  Pass the enclosing git_attr_check instance
instead, so that they will have access to new fields we will add to
the data structure.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 36 ++++++++++++++++++++++++------------
 1 file changed, 24 insertions(+), 12 deletions(-)

diff --git a/attr.c b/attr.c
index a504cb3..219ab11 100644
--- a/attr.c
+++ b/attr.c
@@ -751,14 +751,25 @@ static int attr_check_is_dynamic(const struct git_attr_check *check)
  * check_all_attr. If num is non-zero, only attributes in check[] are
  * collected. Otherwise all attributes are collected.
  */
-static void collect_some_attrs(const char *path, int pathlen, int num,
-			       struct git_attr_check_elem *check)
+static void collect_some_attrs(const char *path, int pathlen,
+			       struct git_attr_check *check)
 
 {
 	struct attr_stack *stk;
 	int i, rem, dirlen;
 	const char *cp, *last_slash = NULL;
 	int basename_offset;
+	int num;
+	struct git_attr_check_elem *celem;
+
+	if (!check) {
+		/* Yuck - ugly git_all_attrs() hack! */
+		celem = NULL;
+		num = 0;
+	} else {
+		celem = check->check;
+		num = check->check_nr;
+	}
 
 	for (cp = path; cp < path + pathlen; cp++) {
 		if (*cp == '/' && cp[1])
@@ -778,9 +789,9 @@ static void collect_some_attrs(const char *path, int pathlen, int num,
 	if (num && !cannot_trust_maybe_real) {
 		rem = 0;
 		for (i = 0; i < num; i++) {
-			if (!check[i].attr->maybe_real) {
+			if (!celem[i].attr->maybe_real) {
 				struct git_attr_check_elem *c;
-				c = check_all_attr + check[i].attr->attr_nr;
+				c = check_all_attr + celem[i].attr->attr_nr;
 				c->value = ATTR__UNSET;
 				rem++;
 			}
@@ -794,18 +805,19 @@ static void collect_some_attrs(const char *path, int pathlen, int num,
 		rem = fill(path, pathlen, basename_offset, stk, rem);
 }
 
-static int git_check_attrs(const char *path, int pathlen, int num,
-			   struct git_attr_check_elem *check)
+static int git_check_attrs(const char *path, int pathlen,
+			   struct git_attr_check *check)
 {
 	int i;
+	struct git_attr_check_elem *celem = check->check;
 
-	collect_some_attrs(path, pathlen, num, check);
+	collect_some_attrs(path, pathlen, check);
 
-	for (i = 0; i < num; i++) {
-		const char *value = check_all_attr[check[i].attr->attr_nr].value;
+	for (i = 0; i < check->check_nr; i++) {
+		const char *value = check_all_attr[celem[i].attr->attr_nr].value;
 		if (value == ATTR__UNKNOWN)
 			value = ATTR__UNSET;
-		check[i].value = value;
+		celem[i].value = value;
 	}
 
 	return 0;
@@ -816,7 +828,7 @@ void git_all_attrs(const char *path, struct git_attr_check *check)
 	int i;
 
 	git_attr_check_clear(check);
-	collect_some_attrs(path, strlen(path), 0, NULL);
+	collect_some_attrs(path, strlen(path), NULL);
 
 	for (i = 0; i < attr_nr; i++) {
 		const char *name = check_all_attr[i].attr->name;
@@ -845,7 +857,7 @@ int git_check_attr_counted(const char *path, int pathlen,
 			   struct git_attr_check *check)
 {
 	check->finalized = 1;
-	return git_check_attrs(path, pathlen, check->check_nr, check->check);
+	return git_check_attrs(path, pathlen, check);
 }
 
 int git_check_attr(const char *path, struct git_attr_check *check)
-- 
2.10.1.469.g00a8914

[PATCH 20/35] attr.c: rename a local variable check

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Throughout this series, we are trying to use "check" to name an
instance of "git_attr_check" structure; let's rename a "check" that
refers to an array whose elements are git_attr_check_elem to avoid
confusion.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/attr.c b/attr.c
index 219ab11..e18098c 100644
--- a/attr.c
+++ b/attr.c
@@ -682,12 +682,12 @@ static int macroexpand_one(int attr_nr, int rem);
 
 static int fill_one(const char *what, struct match_attr *a, int rem)
 {
-	struct git_attr_check_elem *check = check_all_attr;
+	struct git_attr_check_elem *celem = check_all_attr;
 	int i;
 
 	for (i = a->num_attr - 1; 0 < rem && 0 <= i; i--) {
 		struct git_attr *attr = a->state[i].attr;
-		const char **n = &(check[attr->attr_nr].value);
+		const char **n = &(celem[attr->attr_nr].value);
 		const char *v = a->state[i].setto;
 
 		if (*n == ATTR__UNKNOWN) {
-- 
2.10.1.469.g00a8914

[PATCH 21/35] attr.c: correct ugly hack for git_all_attrs()

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

The collect_some_attrs() function has an ugly hack since

06a604e6 (attr: avoid heavy work when we know the specified attr is
not defined, 2014-12-28) added an optimization that relies on the
fact that the caller knows what attributes it is interested in, so
that we can leave once we know the final answer for all the
attributes the caller asked.

git_all_attrs() that asks "what attributes are on this path?"
however does not know what attributes it is interested in, other
than the vague "we are interested in all of them", which is not a
very useful thing to say.  As a way to disable this optimization
for this caller, the said commit added a code to skip it when
the caller passes a NULL for the check structure.

However, it skipped the optimization not when check is NULL, but
when the number of attributes being checked is 0, which is
unnecessarily pessimistic.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/attr.c b/attr.c
index e18098c..48460d2 100644
--- a/attr.c
+++ b/attr.c
@@ -748,8 +748,8 @@ static int attr_check_is_dynamic(const struct git_attr_check *check)
 
 /*
  * Collect attributes for path into the array pointed to by
- * check_all_attr. If num is non-zero, only attributes in check[] are
- * collected. Otherwise all attributes are collected.
+ * check_all_attr.  If check is not NULL, only attributes in
+ * check[] are collected. Otherwise all attributes are collected.
  */
 static void collect_some_attrs(const char *path, int pathlen,
 			       struct git_attr_check *check)
@@ -759,17 +759,6 @@ static void collect_some_attrs(const char *path, int pathlen,
 	int i, rem, dirlen;
 	const char *cp, *last_slash = NULL;
 	int basename_offset;
-	int num;
-	struct git_attr_check_elem *celem;
-
-	if (!check) {
-		/* Yuck - ugly git_all_attrs() hack! */
-		celem = NULL;
-		num = 0;
-	} else {
-		celem = check->check;
-		num = check->check_nr;
-	}
 
 	for (cp = path; cp < path + pathlen; cp++) {
 		if (*cp == '/' && cp[1])
@@ -786,9 +775,12 @@ static void collect_some_attrs(const char *path, int pathlen,
 	prepare_attr_stack(path, dirlen);
 	for (i = 0; i < attr_nr; i++)
 		check_all_attr[i].value = ATTR__UNKNOWN;
-	if (num && !cannot_trust_maybe_real) {
+
+	if (check && !cannot_trust_maybe_real) {
+		struct git_attr_check_elem *celem = check->check;
+
 		rem = 0;
-		for (i = 0; i < num; i++) {
+		for (i = 0; i < check->check_nr; i++) {
 			if (!celem[i].attr->maybe_real) {
 				struct git_attr_check_elem *c;
 				c = check_all_attr + celem[i].attr->attr_nr;
@@ -796,7 +788,7 @@ static void collect_some_attrs(const char *path, int pathlen,
 				rem++;
 			}
 		}
-		if (rem == num)
+		if (rem == check->check_nr)
 			return;
 	}
 
-- 
2.10.1.469.g00a8914

[PATCH 22/35] attr.c: introduce empty_attr_check_elems()

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

One codepath needs to just empty the git_attr_check_elem array in
the git_attr_check structure, without releasing the entire resource.
Introduce a helper to do so and rewrite git_attr_check_clear() using
it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/attr.c b/attr.c
index 48460d2..5bb925d 100644
--- a/attr.c
+++ b/attr.c
@@ -746,6 +746,14 @@ static int attr_check_is_dynamic(const struct git_attr_check *check)
 	return (void *)(check->check) != (void *)(check + 1);
 }
 
+static void empty_attr_check_elems(struct git_attr_check *check)
+{
+	if (!attr_check_is_dynamic(check))
+		die("BUG: emptying a statically initialized git_attr_check");
+	check->check_nr = 0;
+	check->finalized = 0;
+}
+
 /*
  * Collect attributes for path into the array pointed to by
  * check_all_attr.  If check is not NULL, only attributes in
@@ -912,12 +920,11 @@ struct git_attr_check_elem *git_attr_check_append(struct git_attr_check *check,
 
 void git_attr_check_clear(struct git_attr_check *check)
 {
+	empty_attr_check_elems(check);
 	if (!attr_check_is_dynamic(check))
 		die("BUG: clearing a statically initialized git_attr_check");
 	free(check->check);
-	check->check_nr = 0;
 	check->check_alloc = 0;
-	check->finalized = 0;
 }
 
 void git_attr_check_free(struct git_attr_check *check)
-- 
2.10.1.469.g00a8914

[PATCH 23/35] attr.c: always pass check[] to collect_some_attrs()

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

This function used to be called with check=NULL to signal it to
collect all attributes in the global check_all_attr[] array.

Because the longer term plan is to allocate check_all_attr[] and
attr_stack data structures per git_attr_check instance (i.e. "check"
here) to make the attr subsystem thread-safe, it is unacceptable.

Pass "Are we grabbing all attributes defined in the system?" bit as
a separate argument and pass it from the callers.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 37 +++++++++++++++++++------------------
 1 file changed, 19 insertions(+), 18 deletions(-)

diff --git a/attr.c b/attr.c
index 5bb925d..246a5d0 100644
--- a/attr.c
+++ b/attr.c
@@ -756,11 +756,12 @@ static void empty_attr_check_elems(struct git_attr_check *check)
 
 /*
  * Collect attributes for path into the array pointed to by
- * check_all_attr.  If check is not NULL, only attributes in
- * check[] are collected. Otherwise all attributes are collected.
+ * check_all_attr.  If collect_all is zero, only attributes in
+ * check[] are collected.  Otherwise, check[] is cleared and
+ * any and all attributes that are visible are collected in it.
  */
 static void collect_some_attrs(const char *path, int pathlen,
-			       struct git_attr_check *check)
+			       struct git_attr_check *check, int collect_all)
 
 {
 	struct attr_stack *stk;
@@ -781,10 +782,11 @@ static void collect_some_attrs(const char *path, int pathlen,
 	}
 
 	prepare_attr_stack(path, dirlen);
+
 	for (i = 0; i < attr_nr; i++)
 		check_all_attr[i].value = ATTR__UNKNOWN;
 
-	if (check && !cannot_trust_maybe_real) {
+	if (!collect_all && !cannot_trust_maybe_real) {
 		struct git_attr_check_elem *celem = check->check;
 
 		rem = 0;
@@ -803,6 +805,17 @@ static void collect_some_attrs(const char *path, int pathlen,
 	rem = attr_nr;
 	for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
 		rem = fill(path, pathlen, basename_offset, stk, rem);
+
+	if (collect_all) {
+		empty_attr_check_elems(check);
+		for (i = 0; i < attr_nr; i++) {
+			const struct git_attr *attr = check_all_attr[i].attr;
+			const char *value = check_all_attr[i].value;
+			if (value == ATTR__UNSET || value == ATTR__UNKNOWN)
+				continue;
+			git_attr_check_append(check, attr)->value = value;
+		}
+	}
 }
 
 static int git_check_attrs(const char *path, int pathlen,
@@ -811,7 +824,7 @@ static int git_check_attrs(const char *path, int pathlen,
 	int i;
 	struct git_attr_check_elem *celem = check->check;
 
-	collect_some_attrs(path, pathlen, check);
+	collect_some_attrs(path, pathlen, check, 0);
 
 	for (i = 0; i < check->check_nr; i++) {
 		const char *value = check_all_attr[celem[i].attr->attr_nr].value;
@@ -825,19 +838,7 @@ static int git_check_attrs(const char *path, int pathlen,
 
 void git_all_attrs(const char *path, struct git_attr_check *check)
 {
-	int i;
-
-	git_attr_check_clear(check);
-	collect_some_attrs(path, strlen(path), NULL);
-
-	for (i = 0; i < attr_nr; i++) {
-		const char *name = check_all_attr[i].attr->name;
-		const char *value = check_all_attr[i].value;
-		if (value == ATTR__UNSET || value == ATTR__UNKNOWN)
-			continue;
-		git_attr_check_append(check, git_attr(name));
-		check->check[check->check_nr - 1].value = value;
-	}
+	collect_some_attrs(path, strlen(path), check, 1);
 }
 
 void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
-- 
2.10.1.469.g00a8914

[PATCH 24/35] attr.c: outline the future plans by heavily commenting

[Stefan Beller]

From: Junio C Hamano <gitster@pobox.com>

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 40 +++++++++++++++++++++++++++++++++++++++-
 1 file changed, 39 insertions(+), 1 deletion(-)

diff --git a/attr.c b/attr.c
index 246a5d0..60d7eec 100644
--- a/attr.c
+++ b/attr.c
@@ -30,6 +30,11 @@ static const char git_attr__unknown[] = "(builtin)unknown";
 #define DEBUG_ATTR 0
 #endif
 
+/*
+ * NEEDSWORK: the global dictionary of the interned attributes
+ * must stay a singleton even after we become thread-ready.
+ * Access to these must be surrounded with mutex when it happens.
+ */
 struct git_attr {
 	struct git_attr *next;
 	unsigned h;
@@ -39,10 +44,19 @@ struct git_attr {
 	char name[FLEX_ARRAY];
 };
 static int attr_nr;
+static struct git_attr *(git_attr_hash[HASHSIZE]);
+
+/*
+ * NEEDSWORK: maybe-real, maybe-macro are not property of
+ * an attribute, as it depends on what .gitattributes are
+ * read.  Once we introduce per git_attr_check attr_stack
+ * and check_all_attr, the optimization based on them will
+ * become unnecessary and can go away.  So is this variable.
+ */
 static int cannot_trust_maybe_real;
 
+/* NEEDSWORK: This will become per git_attr_check */
 static struct git_attr_check_elem *check_all_attr;
-static struct git_attr *(git_attr_hash[HASHSIZE]);
 
 const char *git_attr_name(const struct git_attr *attr)
 {
@@ -117,6 +131,11 @@ static struct git_attr *git_attr_internal(const char *name, int len)
 	a->maybe_real = 0;
 	git_attr_hash[pos] = a;
 
+	/*
+	 * NEEDSWORK: per git_attr_check check_all_attr
+	 * will be initialized a lot more lazily, not
+	 * like this, and not here.
+	 */
 	REALLOC_ARRAY(check_all_attr, attr_nr);
 	check_all_attr[a->attr_nr].attr = a;
 	check_all_attr[a->attr_nr].value = ATTR__UNKNOWN;
@@ -329,6 +348,7 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
  * .gitignore file and info/excludes file as a fallback.
  */
 
+/* NEEDSWORK: This will become per git_attr_check */
 static struct attr_stack {
 	struct attr_stack *prev;
 	char *origin;
@@ -393,6 +413,24 @@ static struct attr_stack *read_attr_from_array(const char **list)
 	return res;
 }
 
+/*
+ * NEEDSWORK: these two are tricky.  The callers assume there is a
+ * single, system-wide global state "where we read attributes from?"
+ * and when the state is flipped by calling git_attr_set_direction(),
+ * attr_stack is discarded so that subsequent attr_check will lazily
+ * read from the right place.  And they do not know or care who called
+ * by them uses the attribute subsystem, hence have no knowledge of
+ * existing git_attr_check instances or future ones that will be
+ * created).
+ *
+ * Probably we need a thread_local that holds these two variables,
+ * and a list of git_attr_check instances (which need to be maintained
+ * by hooking into git_attr_check_alloc(), git_attr_check_initl(), and
+ * git_attr_check_clear().  Then git_attr_set_direction() updates the
+ * fields in that thread_local for these two variables, iterate over
+ * all the active git_attr_check instances and discard the attr_stack
+ * they hold.  Yuck, but it sounds doable.
+ */
 static enum git_attr_direction direction;
 static struct index_state *use_index;
 
-- 
2.10.1.469.g00a8914

[PATCH 25/35] attr: make git_check_attr_counted static

[Stefan Beller]

It's not used outside the attr code, so let's keep it private.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c | 4 ++--
 attr.h | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/attr.c b/attr.c
index 60d7eec..19a3651 100644
--- a/attr.c
+++ b/attr.c
@@ -892,8 +892,8 @@ void git_attr_set_direction(enum git_attr_direction new, struct index_state *ist
 	use_index = istate;
 }
 
-int git_check_attr_counted(const char *path, int pathlen,
-			   struct git_attr_check *check)
+static int git_check_attr_counted(const char *path, int pathlen,
+				  struct git_attr_check *check)
 {
 	check->finalized = 1;
 	return git_check_attrs(path, pathlen, check);
diff --git a/attr.h b/attr.h
index 1c6a6d8..7416b14 100644
--- a/attr.h
+++ b/attr.h
@@ -48,7 +48,6 @@ struct git_attr_check {
 
 extern struct git_attr_check *git_attr_check_initl(const char *, ...);
 extern int git_check_attr(const char *path, struct git_attr_check *);
-extern int git_check_attr_counted(const char *, int, struct git_attr_check *);
 
 extern struct git_attr_check *git_attr_check_alloc(void);
 extern struct git_attr_check_elem *git_attr_check_append(struct git_attr_check *, const struct git_attr *);
-- 
2.10.1.469.g00a8914

[PATCH 26/35] attr: convert to new threadsafe API

[Stefan Beller]

This revamps the API of the attr subsystem to be thread safe.
Before we had the question and its results in one struct type.
The typical usage of the API was

    static struct git_attr_check *check;

    if (!check)
        check = git_attr_check_initl("text", NULL);

    git_check_attr(path, check);
    act_on(check->value[0]);

This has a couple of issues when it comes to thread safety:

* the initialization is racy in this implementation. To make it
  thread safe, we need to acquire a mutex, such that only one
  thread is executing the code in git_attr_check_initl.
  As we do not want to introduce a mutex at each call site,
  this is best done in the attr code. However to do so, we need
  to have access to the `check` variable, i.e. the API has to
  look like
    git_attr_check_initl(struct git_attr_check**, ...);
  Then one of the threads calling git_attr_check_initl will
  acquire the mutex and init the `check`, while all other threads
  will wait on the mutex just to realize they're late to the
  party and they'll return with no work done.

* While the check for attributes to be questioned only need to
  be initalized once as that part will be read only after its
  initialisation, the answer may be different for each path.
  Because of that we need to decouple the check and the answer,
  such that each thread can obtain an answer for the path it
  is currently processing.

This commit changes the API and adds locking in
git_attr_check_initl that provides the thread safety for constructing
`struct git_attr_check`.

The usage of the new API will be:

    /*
     * The initl call will thread-safely check whether the
     * struct git_attr_check has been initialized. We only
     * want to do the initialization work once, hence we do
     * that work inside a thread safe environment.
     */
    static struct git_attr_check *check;
    git_attr_check_initl(&check, "text", NULL);

    /* We're just asking for one attribute "text". */
    git_attr_result myresult[1];

    /* Perform the check and act on it: */
    git_check_attr(path, check, myresult);
    act_on(myresult[0].value);

    /*
     * No need to free the check as it is static, hence doesn't leak
     * memory. The result is also static, so no need to free there either.
     */

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

# Conflicts:
#	attr.h

Signed-off-by: Stefan Beller <sbeller@google.com>
---
 Documentation/technical/api-gitattributes.txt | 136 +++++++++++---------
 archive.c                                     |  11 +-
 attr.c                                        | 172 +++++++++++++++++---------
 attr.h                                        |  72 ++++++-----
 builtin/check-attr.c                          |  50 ++++----
 builtin/pack-objects.c                        |  16 +--
 common-main.c                                 |   2 +
 convert.c                                     |  40 +++---
 ll-merge.c                                    |  24 ++--
 userdiff.c                                    |  16 +--
 ws.c                                          |   8 +-
 11 files changed, 323 insertions(+), 224 deletions(-)

diff --git a/Documentation/technical/api-gitattributes.txt b/Documentation/technical/api-gitattributes.txt
index 92fc32a..7dd6616 100644
--- a/Documentation/technical/api-gitattributes.txt
+++ b/Documentation/technical/api-gitattributes.txt
@@ -10,21 +10,23 @@ Data Structure
 
 `struct git_attr`::
 
-	An attribute is an opaque object that is identified by its name.
-	Pass the name to `git_attr()` function to obtain the object of
-	this type.  The internal representation of this structure is
+	The internal representation of this structure is
 	of no interest to the calling programs.  The name of the
 	attribute can be retrieved by calling `git_attr_name()`.
 
-`struct git_attr_check_elem`::
-
-	This structure represents one attribute and its value.
-
 `struct git_attr_check`::
 
-	This structure represents a collection of `git_attr_check_elem`.
+	This structure represents a collection of `struct git_attrs`.
 	It is passed to `git_check_attr()` function, specifying the
-	attributes to check, and receives their values.
+	attributes to check, and receives their values into a corresponding
+	`struct git_attr_result`.
+
+`struct git_attr_result`::
+
+	This structure represents one results for a check, such that an
+	array of `struct git_attr_results` corresponds to a
+	`struct git_attr_check`. The answers given in that array are in
+	the the same order as the check struct.
 
 
 Attribute Values
@@ -32,7 +34,7 @@ Attribute Values
 
 An attribute for a path can be in one of four states: Set, Unset,
 Unspecified or set to a string, and `.value` member of `struct
-git_attr_check` records it.  There are three macros to check these:
+git_attr_result` records it.  There are three macros to check these:
 
 `ATTR_TRUE()`::
 
@@ -53,19 +55,28 @@ value of the attribute for the path.
 Querying Specific Attributes
 ----------------------------
 
-* Prepare `struct git_attr_check` using git_attr_check_initl()
-  function, enumerating the names of attributes whose values you are
-  interested in, terminated with a NULL pointer.  Alternatively, an
-  empty `struct git_attr_check` can be prepared by calling
-  `git_attr_check_alloc()` function and then attributes you want to
-  ask about can be added to it with `git_attr_check_append()`
-  function.
-
-* Call `git_check_attr()` to check the attributes for the path.
-
-* Inspect `git_attr_check` structure to see how each of the
-  attribute in the array is defined for the path.
-
+* Prepare a `struct git_attr_check` using `git_attr_check_initl()` or
+  `git_attr_check_initv()` function, enumerating the names of
+  attributes whose values you are interested in, terminated with
+  a NULL.
+  Preparing the `struct git_attr_check` is thread safe, i.e. you
+  can call it from different threads at the same time; when check
+  determines the initialization is still needed, the threads will
+  use a single global mutex to perform the initialization just once,
+  the others will wait on the the thread to actually perform the
+  initialization.
+
+* Allocate an array of `struct git_attr_result` either on the stack
+  or via `git_attr_result_alloc` on the heap when the result size
+  is not known at compile time.
+
+* Call `git_check_attr()` to check the attributes for the path,
+  the given `git_attr_result` will be filled with the result.
+  You must not change the `struct git_attr_check` after calling
+  `git_check_attr()`.
+
+* Inspect each `git_attr_result` structure to see how
+  each of the attribute in the array is defined for the path.
 
 Example
 -------
@@ -73,31 +84,22 @@ Example
 To see how attributes "crlf" and "ident" are set for different paths.
 
 . Prepare a `struct git_attr_check` with two elements (because
-  we are checking two attributes):
-
-------------
-static struct git_attr_check *check;
-static void setup_check(void)
-{
-	if (check)
-		return; /* already done */
-	check = git_attr_check_initl("crlf", "ident", NULL);
-}
-------------
-
-. Call `git_check_attr()` with the prepared `struct git_attr_check`:
+  we are checking two attributes) and then call `git_check_attr()`
+  with the prepared `struct git_attr_check`:
 
 ------------
 	const char *path;
+	struct git_attr_result result[2];
+	static struct git_attr_check *check;
 
-	setup_check();
-	git_check_attr(path, check);
+	git_attr_check_initl(&check, "crlf", "ident", NULL);
+	git_check_attr(path, check, result);
 ------------
 
-. Act on `.value` member of the result, left in `check->check[]`:
+. Act on `result.value[]`:
 
 ------------
-	const char *value = check->check[0].value;
+	const char *value = result.value[0];
 
 	if (ATTR_TRUE(value)) {
 		The attribute is Set, by listing only the name of the
@@ -116,19 +118,28 @@ static void setup_check(void)
 	}
 ------------
 
-To see how attributes in argv[] are set for different paths, only
-the first step in the above would be different.
+To see how attributes in argv[] are set for different paths, use
+`git_attr_check_initv` instead. When an invalid attr name is given
+both init functions die unconditionally with a non user friendly message.
+So you want to check the attr values first:
 
 ------------
 static struct git_attr_check *check;
 static void setup_check(const char **argv)
 {
-	check = git_attr_check_alloc();
-	while (*argv) {
-		struct git_attr *attr = git_attr(*argv);
-		git_attr_check_append(check, attr);
-		argv++;
+	const char **argv_copy = argv;
+	while (*argv_copy) {
+		const char *name = argv_copy[0];
+		const int len = strlen(argv_copy[0]);
+		if (!attr_name_valid(name, len)) {
+			struct strbuf sb = STRBUF_INIT;
+			invalid_attr_name_message(&sb, name, len);
+			die ("Oops this is bad: %s", sb.buf);
+		}
+		argv_copy++;
 	}
+	git_attr_check_initv(&check, argv);
+	struct git_attr_result *result = git_attr_result_alloc(check);
 }
 ------------
 
@@ -138,17 +149,30 @@ Querying All Attributes
 
 To get the values of all attributes associated with a file:
 
-* Prepare an empty `git_attr_check` structure by calling
-  `git_attr_check_alloc()`.
+* Setup a local variables for the question
+  `struct git_attr_check` as well as a pointer where the result
+  `struct git_attr_result` will be stored. Both should be initialized
+  to NULL.
+
+------------
+  struct git_attr_check *check = NULL;
+  struct git_attr_result *result = NULL;
+------------
+
+* Call `git_all_attrs()`.
 
-* Call `git_all_attrs()`, which populates the `git_attr_check`
-  with the attributes attached to the path.
+------------
+  git_all_attrs(full_path, &check, &result);
+------------
 
-* Iterate over the `git_attr_check.check[]` array to examine
-  the attribute names and values.  The name of the attribute
-  described by a  `git_attr_check.check[]` object can be retrieved via
-  `git_attr_name(check->check[i].attr)`.  (Please note that no items
+* Iterate over the `git_attr_check.attr[]` array to examine the
+  attribute names.  The name of the attribute described by a
+  `git_attr_check.attr[]` object can be retrieved via
+  `git_attr_name(check->attr[i])`.  (Please note that no items
   will be returned for unset attributes, so `ATTR_UNSET()` will return
   false for all returned `git_array_check` objects.)
+  The respective value for an attribute can be found in the same
+  index position in of `git_attr_result`.
 
-* Free the `git_array_check` by calling `git_attr_check_free()`.
+* Clear the variables by calling `git_attr_check_clear()` and
+  `git_attr_result_free()`.
diff --git a/archive.c b/archive.c
index 11e3951..65bc6b7 100644
--- a/archive.c
+++ b/archive.c
@@ -111,6 +111,7 @@ static int write_archive_entry(const unsigned char *sha1, const char *base,
 	struct archiver_args *args = c->args;
 	write_archive_entry_fn_t write_entry = c->write_entry;
 	static struct git_attr_check *check;
+	struct git_attr_result result[2];
 	const char *path_without_prefix;
 	int err;
 
@@ -124,12 +125,12 @@ static int write_archive_entry(const unsigned char *sha1, const char *base,
 		strbuf_addch(&path, '/');
 	path_without_prefix = path.buf + args->baselen;
 
-	if (!check)
-		check = git_attr_check_initl("export-ignore", "export-subst", NULL);
-	if (!git_check_attr(path_without_prefix, check)) {
-		if (ATTR_TRUE(check->check[0].value))
+	git_attr_check_initl(&check, "export-ignore", "export-subst", NULL);
+
+	if (!git_check_attr(path_without_prefix, check, result)) {
+		if (ATTR_TRUE(result[0].value))
 			return 0;
-		args->convert = ATTR_TRUE(check->check[1].value);
+		args->convert = ATTR_TRUE(result[1].value);
 	}
 
 	if (S_ISDIR(mode) || S_ISGITLINK(mode)) {
diff --git a/attr.c b/attr.c
index 19a3651..32ec453 100644
--- a/attr.c
+++ b/attr.c
@@ -14,6 +14,8 @@
 #include "dir.h"
 #include "utf8.h"
 #include "quote.h"
+#include "thread-utils.h"
+#include "argv-array.h"
 
 const char git_attr__true[] = "(builtin)true";
 const char git_attr__false[] = "\0(builtin)false";
@@ -46,6 +48,21 @@ struct git_attr {
 static int attr_nr;
 static struct git_attr *(git_attr_hash[HASHSIZE]);
 
+#ifndef NO_PTHREADS
+
+static pthread_mutex_t attr_mutex;
+#define attr_lock()		pthread_mutex_lock(&attr_mutex)
+#define attr_unlock()		pthread_mutex_unlock(&attr_mutex)
+void attr_start(void) { pthread_mutex_init(&attr_mutex, NULL); }
+
+#else
+
+#define attr_lock()		(void)0
+#define attr_unlock()		(void)0
+void attr_start(void) {;}
+
+#endif /* NO_PTHREADS */
+
 /*
  * NEEDSWORK: maybe-real, maybe-macro are not property of
  * an attribute, as it depends on what .gitattributes are
@@ -55,6 +72,16 @@ static struct git_attr *(git_attr_hash[HASHSIZE]);
  */
 static int cannot_trust_maybe_real;
 
+/*
+ * Send one or more git_attr_check to git_check_attrs(), and
+ * each 'value' member tells what its value is.
+ * Unset one is returned as NULL.
+ */
+struct git_attr_check_elem {
+	const struct git_attr *attr;
+	const char *value;
+};
+
 /* NEEDSWORK: This will become per git_attr_check */
 static struct git_attr_check_elem *check_all_attr;
 
@@ -781,7 +808,7 @@ static int macroexpand_one(int nr, int rem)
 
 static int attr_check_is_dynamic(const struct git_attr_check *check)
 {
-	return (void *)(check->check) != (void *)(check + 1);
+	return (void *)(check->attr) != (void *)(check + 1);
 }
 
 static void empty_attr_check_elems(struct git_attr_check *check)
@@ -799,7 +826,9 @@ static void empty_attr_check_elems(struct git_attr_check *check)
  * any and all attributes that are visible are collected in it.
  */
 static void collect_some_attrs(const char *path, int pathlen,
-			       struct git_attr_check *check, int collect_all)
+			       struct git_attr_check *check,
+			       struct git_attr_result **result,
+			       int collect_all)
 
 {
 	struct attr_stack *stk;
@@ -825,13 +854,11 @@ static void collect_some_attrs(const char *path, int pathlen,
 		check_all_attr[i].value = ATTR__UNKNOWN;
 
 	if (!collect_all && !cannot_trust_maybe_real) {
-		struct git_attr_check_elem *celem = check->check;
-
 		rem = 0;
 		for (i = 0; i < check->check_nr; i++) {
-			if (!celem[i].attr->maybe_real) {
+			if (!check->attr[i]->maybe_real) {
 				struct git_attr_check_elem *c;
-				c = check_all_attr + celem[i].attr->attr_nr;
+				c = check_all_attr + check->attr[i]->attr_nr;
 				c->value = ATTR__UNSET;
 				rem++;
 			}
@@ -845,38 +872,53 @@ static void collect_some_attrs(const char *path, int pathlen,
 		rem = fill(path, pathlen, basename_offset, stk, rem);
 
 	if (collect_all) {
-		empty_attr_check_elems(check);
+		int check_nr = 0, check_alloc = 0;
+		const char **res = NULL;
+
 		for (i = 0; i < attr_nr; i++) {
 			const struct git_attr *attr = check_all_attr[i].attr;
 			const char *value = check_all_attr[i].value;
 			if (value == ATTR__UNSET || value == ATTR__UNKNOWN)
 				continue;
-			git_attr_check_append(check, attr)->value = value;
+
+			ALLOC_GROW(check->attr, check->check_nr + 1, check->check_alloc);
+			check->attr[check->check_nr++] = attr;
+
+			ALLOC_GROW(res, check_nr + 1, check_alloc);
+			res[check_nr++] = value;
 		}
+
+		*result = git_attr_result_alloc(check);
+		for (i = 0; i < check->check_nr; i++)
+			(*result)[i].value = res[i];
+
+		free(res);
 	}
 }
 
 static int git_check_attrs(const char *path, int pathlen,
-			   struct git_attr_check *check)
+			   struct git_attr_check *check,
+			   struct git_attr_result *result)
 {
 	int i;
-	struct git_attr_check_elem *celem = check->check;
 
-	collect_some_attrs(path, pathlen, check, 0);
+	collect_some_attrs(path, pathlen, check, &result, 0);
 
 	for (i = 0; i < check->check_nr; i++) {
-		const char *value = check_all_attr[celem[i].attr->attr_nr].value;
+		const char *value = check_all_attr[check->attr[i]->attr_nr].value;
 		if (value == ATTR__UNKNOWN)
 			value = ATTR__UNSET;
-		celem[i].value = value;
+		result[i].value = value;
 	}
 
 	return 0;
 }
 
-void git_all_attrs(const char *path, struct git_attr_check *check)
+void git_all_attrs(const char *path,
+		   struct git_attr_check *check,
+		   struct git_attr_result **result)
 {
-	collect_some_attrs(path, strlen(path), check, 1);
+	collect_some_attrs(path, strlen(path), check, result, 1);
 }
 
 void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
@@ -892,69 +934,79 @@ void git_attr_set_direction(enum git_attr_direction new, struct index_state *ist
 	use_index = istate;
 }
 
-static int git_check_attr_counted(const char *path, int pathlen,
-				  struct git_attr_check *check)
+int git_check_attr(const char *path,
+		    struct git_attr_check *check,
+		    struct git_attr_result *result)
 {
 	check->finalized = 1;
-	return git_check_attrs(path, pathlen, check);
+	return git_check_attrs(path, strlen(path), check, result);
 }
 
-int git_check_attr(const char *path, struct git_attr_check *check)
+static void git_attr_check_initv_unlocked(struct git_attr_check **check_,
+				 const char **argv)
 {
-	return git_check_attr_counted(path, strlen(path), check);
+	int cnt;
+	struct git_attr_check *check;
+
+	for (cnt = 0; argv[cnt] != NULL; cnt++)
+		;
+
+	check = xcalloc(1, sizeof(*check) + cnt * sizeof(*(check->attr)));
+	check->check_nr = cnt;
+	check->finalized = 1;
+	check->attr = (const struct git_attr **)(check + 1);
+
+	for (cnt = 0; cnt < check->check_nr; cnt++) {
+		struct git_attr *attr = git_attr(argv[cnt]);
+		if (!attr)
+			die("BUG: %s: not a valid attribute name", argv[cnt]);
+		check->attr[cnt] = attr;
+	}
+
+	*check_ = check;
 }
 
-struct git_attr_check *git_attr_check_initl(const char *one, ...)
+void git_attr_check_initl(struct git_attr_check **check,
+			  const char *one, ...)
 {
-	struct git_attr_check *check;
 	int cnt;
 	va_list params;
 	const char *param;
+	struct argv_array attrs = ARGV_ARRAY_INIT;
+
+	attr_lock();
+	if (*check) {
+		attr_unlock();
+		return;
+	}
 
 	va_start(params, one);
+	argv_array_push(&attrs, one);
 	for (cnt = 1; (param = va_arg(params, const char *)) != NULL; cnt++)
-		;
+		argv_array_push(&attrs, param);
 	va_end(params);
-	check = xcalloc(1,
-			sizeof(*check) + cnt * sizeof(*(check->check)));
-	check->check_nr = cnt;
-	check->finalized = 1;
-	check->check = (struct git_attr_check_elem *)(check + 1);
 
-	check->check[0].attr = git_attr(one);
-	va_start(params, one);
-	for (cnt = 1; cnt < check->check_nr; cnt++) {
-		struct git_attr *attr;
-		param = va_arg(params, const char *);
-		if (!param)
-			die("BUG: counted %d != ended at %d",
-			    check->check_nr, cnt);
-		attr = git_attr(param);
-		if (!attr)
-			die("BUG: %s: not a valid attribute name", param);
-		check->check[cnt].attr = attr;
-	}
-	va_end(params);
-	return check;
+	git_attr_check_initv_unlocked(check, attrs.argv);
+
+	attr_unlock();
+	argv_array_clear(&attrs);
 }
 
-struct git_attr_check *git_attr_check_alloc(void)
+void git_attr_check_initv(struct git_attr_check **check, const char **argv)
 {
-	return xcalloc(1, sizeof(struct git_attr_check));
+	attr_lock();
+	if (*check) {
+		attr_unlock();
+		return;
+	}
+	git_attr_check_initv_unlocked(check, argv);
+
+	attr_unlock();
 }
 
-struct git_attr_check_elem *git_attr_check_append(struct git_attr_check *check,
-						  const struct git_attr *attr)
+struct git_attr_result *git_attr_result_alloc(struct git_attr_check *check)
 {
-	struct git_attr_check_elem *elem;
-	if (check->finalized)
-		die("BUG: append after git_attr_check structure is finalized");
-	if (!attr_check_is_dynamic(check))
-		die("BUG: appending to a statically initialized git_attr_check");
-	ALLOC_GROW(check->check, check->check_nr + 1, check->check_alloc);
-	elem = &check->check[check->check_nr++];
-	elem->attr = attr;
-	return elem;
+	return xcalloc(1, sizeof(struct git_attr_result) * check->check_nr);
 }
 
 void git_attr_check_clear(struct git_attr_check *check)
@@ -962,12 +1014,12 @@ void git_attr_check_clear(struct git_attr_check *check)
 	empty_attr_check_elems(check);
 	if (!attr_check_is_dynamic(check))
 		die("BUG: clearing a statically initialized git_attr_check");
-	free(check->check);
+	free(check->attr);
 	check->check_alloc = 0;
 }
 
-void git_attr_check_free(struct git_attr_check *check)
+void git_attr_result_free(struct git_attr_result *result)
 {
-	git_attr_check_clear(check);
-	free(check);
+	/* No need to free values as they are interned. */
+	free(result);
 }
diff --git a/attr.h b/attr.h
index 7416b14..1a50288 100644
--- a/attr.h
+++ b/attr.h
@@ -1,14 +1,14 @@
 #ifndef ATTR_H
 #define ATTR_H
 
-/* An attribute is a pointer to this opaque structure */
-struct git_attr;
-
 /*
- * Given a string, return the gitattribute object that
- * corresponds to it.
+ * Must be called on platforms that do not support static initialization
+ * of mutexes.
  */
-struct git_attr *git_attr(const char *);
+extern void attr_start(void);
+
+/* An attribute is a pointer to this opaque structure */
+struct git_attr;
 
 /*
  * Return the name of the attribute represented by the argument.  The
@@ -29,44 +29,48 @@ extern const char git_attr__false[];
 #define ATTR_FALSE(v) ((v) == git_attr__false)
 #define ATTR_UNSET(v) ((v) == NULL)
 
-/*
- * Send one or more git_attr_check to git_check_attrs(), and
- * each 'value' member tells what its value is.
- * Unset one is returned as NULL.
- */
-struct git_attr_check_elem {
-	const struct git_attr *attr;
-	const char *value;
-};
-
 struct git_attr_check {
 	int finalized;
 	int check_nr;
 	int check_alloc;
-	struct git_attr_check_elem *check;
+	const struct git_attr **attr;
 };
+#define GIT_ATTR_CHECK_INIT {0, 0, 0, NULL}
 
-extern struct git_attr_check *git_attr_check_initl(const char *, ...);
-extern int git_check_attr(const char *path, struct git_attr_check *);
-
-extern struct git_attr_check *git_attr_check_alloc(void);
-extern struct git_attr_check_elem *git_attr_check_append(struct git_attr_check *, const struct git_attr *);
-
-extern void git_attr_check_clear(struct git_attr_check *);
-extern void git_attr_check_free(struct git_attr_check *);
+struct git_attr_result {
+	const char *value;
+};
 
 /*
- * Return the name of the attribute represented by the argument.  The
- * return value is a pointer to a null-delimited string that is part
- * of the internal data structure; it should not be modified or freed.
+ * Initialize the `git_attr_check` via one of the following three functions:
+ *
+ * git_all_attrs         allocates a check and fills in all attributes and
+ *                       results that are set for the given path.
+ * git_attr_check_initl  takes a pointer to where the check will be initialized,
+ *                       followed by all attributes that are to be checked.
+ * git_attr_check_initv  takes a pointer to where the check will be initialized,
+ *                       and a NULL terminated array of attributes.
+ *
+ * All initialization methods are thread safe.
+ * To allocate memory for the result of a given check,
+ * use git_attr_result_alloc.
  */
-extern const char *git_attr_name(const struct git_attr *);
+extern void git_attr_check_initl(struct git_attr_check **,
+				 const char *, ...);
+extern void git_attr_check_initv(struct git_attr_check **,
+				 const char **);
+extern void git_all_attrs(const char *path,
+			  struct git_attr_check *,
+			  struct git_attr_result **);
+extern struct git_attr_result *git_attr_result_alloc(struct git_attr_check *check);
 
-/*
- * Retrieve all attributes that apply to the specified path.
- * check holds the attributes and their values.
- */
-void git_all_attrs(const char *path, struct git_attr_check *check);
+/* Query a path for its attributes */
+extern int git_check_attr(const char *path,
+			  struct git_attr_check *,
+			  struct git_attr_result *result);
+
+extern void git_attr_check_clear(struct git_attr_check *);
+extern void git_attr_result_free(struct git_attr_result *);
 
 enum git_attr_direction {
 	GIT_ATTR_CHECKIN,
diff --git a/builtin/check-attr.c b/builtin/check-attr.c
index ec61476..418c3da 100644
--- a/builtin/check-attr.c
+++ b/builtin/check-attr.c
@@ -3,6 +3,7 @@
 #include "attr.h"
 #include "quote.h"
 #include "parse-options.h"
+#include "argv-array.h"
 
 static int all_attrs;
 static int cached_attrs;
@@ -24,13 +25,14 @@ static const struct option check_attr_options[] = {
 	OPT_END()
 };
 
-static void output_attr(struct git_attr_check *check, const char *file)
+static void output_attr(struct git_attr_check *check,
+			struct git_attr_result *result, const char *file)
 {
 	int j;
 	int cnt = check->check_nr;
 
 	for (j = 0; j < cnt; j++) {
-		const char *value = check->check[j].value;
+		const char *value = result[j].value;
 
 		if (ATTR_TRUE(value))
 			value = "set";
@@ -44,11 +46,11 @@ static void output_attr(struct git_attr_check *check, const char *file)
 			       "%s%c" /* attrname */
 			       "%s%c" /* attrvalue */,
 			       file, 0,
-			       git_attr_name(check->check[j].attr), 0, value, 0);
+			       git_attr_name(check->attr[j]), 0, value, 0);
 		} else {
 			quote_c_style(file, NULL, stdout, 0);
 			printf(": %s: %s\n",
-			       git_attr_name(check->check[j].attr), value);
+			       git_attr_name(check->attr[j]), value);
 		}
 	}
 }
@@ -59,16 +61,20 @@ static void check_attr(const char *prefix,
 {
 	char *full_path =
 		prefix_path(prefix, prefix ? strlen(prefix) : 0, file);
+	struct git_attr_check local_check = GIT_ATTR_CHECK_INIT;
+	struct git_attr_result *result = NULL;
+
 	if (check != NULL) {
-		if (git_check_attr(full_path, check))
-			die("git_check_attr died");
-		output_attr(check, file);
+		result = git_attr_result_alloc(check);
+		git_check_attr(full_path, check, result);
 	} else {
-		check = git_attr_check_alloc();
-		git_all_attrs(full_path, check);
-		output_attr(check, file);
-		git_attr_check_free(check);
+		git_all_attrs(full_path, &local_check, &result);
+		check = &local_check;
 	}
+	output_attr(check, result, file);
+	git_attr_check_clear(&local_check);
+
+	git_attr_result_free(result);
 	free(full_path);
 }
 
@@ -102,7 +108,7 @@ static NORETURN void error_with_usage(const char *msg)
 
 int cmd_check_attr(int argc, const char **argv, const char *prefix)
 {
-	struct git_attr_check *check;
+	struct git_attr_check *check = NULL;
 	int cnt, i, doubledash, filei;
 
 	if (!is_bare_repository())
@@ -162,17 +168,19 @@ int cmd_check_attr(int argc, const char **argv, const char *prefix)
 			error_with_usage("No file specified");
 	}
 
-	if (all_attrs) {
-		check = NULL;
-	} else {
-		check = git_attr_check_alloc();
+	if (!all_attrs) {
+		struct argv_array attrs = ARGV_ARRAY_INIT;
 		for (i = 0; i < cnt; i++) {
-			struct git_attr *a = git_attr(argv[i]);
-			if (!a)
-				return error("%s: not a valid attribute name",
-					     argv[i]);
-			git_attr_check_append(check, a);
+			if (!attr_name_valid(argv[i], strlen(argv[i]))) {
+				struct strbuf sb = STRBUF_INIT;
+				invalid_attr_name_message(&sb, argv[i],
+							  strlen(argv[i]));
+				return error("%s", strbuf_detach(&sb, NULL));
+			}
+			argv_array_push(&attrs, argv[i]);
 		}
+		git_attr_check_initv(&check, attrs.argv);
+		argv_array_clear(&attrs);
 	}
 
 	if (stdin_paths)
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 3918c07..3751836 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -899,14 +899,16 @@ static void write_pack_file(void)
 static int no_try_delta(const char *path)
 {
 	static struct git_attr_check *check;
+	int ret = 0;
+	struct git_attr_result result[1];
 
-	if (!check)
-		check = git_attr_check_initl("delta", NULL);
-	if (git_check_attr(path, check))
-		return 0;
-	if (ATTR_FALSE(check->check[0].value))
-		return 1;
-	return 0;
+	git_attr_check_initl(&check, "delta", NULL);
+
+	if (!git_check_attr(path, check, result)) {
+		if (ATTR_FALSE(result[0].value))
+			ret = 1;
+	}
+	return ret;
 }
 
 /*
diff --git a/common-main.c b/common-main.c
index 44a29e8..d4699cd 100644
--- a/common-main.c
+++ b/common-main.c
@@ -1,5 +1,6 @@
 #include "cache.h"
 #include "exec_cmd.h"
+#include "attr.h"
 
 /*
  * Many parts of Git have subprograms communicate via pipe, expect the
@@ -32,6 +33,7 @@ int main(int argc, const char **argv)
 	sanitize_stdfds();
 
 	git_setup_gettext();
+	attr_start();
 
 	argv[0] = git_extract_argv0_path(argv[0]);
 
diff --git a/convert.c b/convert.c
index bb2435a..fe861ce 100644
--- a/convert.c
+++ b/convert.c
@@ -718,9 +718,9 @@ static int ident_to_worktree(const char *path, const char *src, size_t len,
 	return 1;
 }
 
-static enum crlf_action git_path_check_crlf(struct git_attr_check_elem *check)
+static enum crlf_action git_path_check_crlf(struct git_attr_result *result)
 {
-	const char *value = check->value;
+	const char *value = result->value;
 
 	if (ATTR_TRUE(value))
 		return CRLF_TEXT;
@@ -735,9 +735,9 @@ static enum crlf_action git_path_check_crlf(struct git_attr_check_elem *check)
 	return CRLF_UNDEFINED;
 }
 
-static enum eol git_path_check_eol(struct git_attr_check_elem *check)
+static enum eol git_path_check_eol(struct git_attr_result *result)
 {
-	const char *value = check->value;
+	const char *value = result->value;
 
 	if (ATTR_UNSET(value))
 		;
@@ -748,9 +748,9 @@ static enum eol git_path_check_eol(struct git_attr_check_elem *check)
 	return EOL_UNSET;
 }
 
-static struct convert_driver *git_path_check_convert(struct git_attr_check_elem *check)
+static struct convert_driver *git_path_check_convert(struct git_attr_result *result)
 {
-	const char *value = check->value;
+	const char *value = result->value;
 	struct convert_driver *drv;
 
 	if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
@@ -761,9 +761,9 @@ static struct convert_driver *git_path_check_convert(struct git_attr_check_elem
 	return NULL;
 }
 
-static int git_path_check_ident(struct git_attr_check_elem *check)
+static int git_path_check_ident(struct git_attr_result *result)
 {
-	const char *value = check->value;
+	const char *value = result->value;
 
 	return !!ATTR_TRUE(value);
 }
@@ -778,25 +778,27 @@ struct conv_attrs {
 static void convert_attrs(struct conv_attrs *ca, const char *path)
 {
 	static struct git_attr_check *check;
+	static int init_user_convert_tail;
+	struct git_attr_result result[5];
 
-	if (!check) {
-		check = git_attr_check_initl("crlf", "ident",
-					     "filter", "eol", "text",
-					     NULL);
+	git_attr_check_initl(&check, "crlf", "ident", "filter",
+			     "eol", "text", NULL);
+
+	if (!init_user_convert_tail) {
 		user_convert_tail = &user_convert;
 		git_config(read_convert_config, NULL);
+		init_user_convert_tail = 1;
 	}
 
-	if (!git_check_attr(path, check)) {
-		struct git_attr_check_elem *ccheck = check->check;
-		ca->crlf_action = git_path_check_crlf(ccheck + 4);
+	if (!git_check_attr(path, check, result)) {
+		ca->crlf_action = git_path_check_crlf(&result[4]);
 		if (ca->crlf_action == CRLF_UNDEFINED)
-			ca->crlf_action = git_path_check_crlf(ccheck + 0);
+			ca->crlf_action = git_path_check_crlf(&result[0]);
 		ca->attr_action = ca->crlf_action;
-		ca->ident = git_path_check_ident(ccheck + 1);
-		ca->drv = git_path_check_convert(ccheck + 2);
+		ca->ident = git_path_check_ident(&result[1]);
+		ca->drv = git_path_check_convert(&result[2]);
 		if (ca->crlf_action != CRLF_BINARY) {
-			enum eol eol_attr = git_path_check_eol(ccheck + 3);
+			enum eol eol_attr = git_path_check_eol(&result[3]);
 			if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
 				ca->crlf_action = CRLF_AUTO_INPUT;
 			else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
diff --git a/ll-merge.c b/ll-merge.c
index bc6479c..d71354a 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -353,12 +353,14 @@ int ll_merge(mmbuffer_t *result_buf,
 	     mmfile_t *theirs, const char *their_label,
 	     const struct ll_merge_options *opts)
 {
-	static struct git_attr_check *check;
 	static const struct ll_merge_options default_opts;
 	const char *ll_driver_name = NULL;
 	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 	const struct ll_merge_driver *driver;
 
+	static struct git_attr_check *check;
+	struct git_attr_result result[2];
+
 	if (!opts)
 		opts = &default_opts;
 
@@ -368,13 +370,12 @@ int ll_merge(mmbuffer_t *result_buf,
 		normalize_file(theirs, path);
 	}
 
-	if (!check)
-		check = git_attr_check_initl("merge", "conflict-marker-size", NULL);
+	git_attr_check_initl(&check, "merge", "conflict-marker-size", NULL);
 
-	if (!git_check_attr(path, check)) {
-		ll_driver_name = check->check[0].value;
-		if (check->check[1].value) {
-			marker_size = atoi(check->check[1].value);
+	if (!git_check_attr(path, check, result)) {
+		ll_driver_name = result[0].value;
+		if (result[1].value) {
+			marker_size = atoi(result[1].value);
 			if (marker_size <= 0)
 				marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 		}
@@ -395,11 +396,12 @@ int ll_merge_marker_size(const char *path)
 {
 	static struct git_attr_check *check;
 	int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
+	struct git_attr_result result[1];
+
+	git_attr_check_initl(&check, "conflict-marker-size", NULL);
 
-	if (!check)
-		check = git_attr_check_initl("conflict-marker-size", NULL);
-	if (!git_check_attr(path, check) && check->check[0].value) {
-		marker_size = atoi(check->check[0].value);
+	if (!git_check_attr(path, check, result) && !ATTR_UNSET(result[0].value)) {
+		marker_size = atoi(result[0].value);
 		if (marker_size <= 0)
 			marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 	}
diff --git a/userdiff.c b/userdiff.c
index 46dfd32..1d6d363 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -263,21 +263,23 @@ struct userdiff_driver *userdiff_find_by_name(const char *name) {
 struct userdiff_driver *userdiff_find_by_path(const char *path)
 {
 	static struct git_attr_check *check;
+	struct git_attr_result result[1];
 
-	if (!check)
-		check = git_attr_check_initl("diff", NULL);
 	if (!path)
 		return NULL;
-	if (git_check_attr(path, check))
+
+	git_attr_check_initl(&check, "diff", NULL);
+
+	if (git_check_attr(path, check, result))
 		return NULL;
 
-	if (ATTR_TRUE(check->check[0].value))
+	if (ATTR_TRUE(result[0].value))
 		return &driver_true;
-	if (ATTR_FALSE(check->check[0].value))
+	if (ATTR_FALSE(result[0].value))
 		return &driver_false;
-	if (ATTR_UNSET(check->check[0].value))
+	if (ATTR_UNSET(result[0].value))
 		return NULL;
-	return userdiff_find_by_name(check->check[0].value);
+	return userdiff_find_by_name(result[0].value);
 }
 
 struct userdiff_driver *userdiff_get_textconv(struct userdiff_driver *driver)
diff --git a/ws.c b/ws.c
index bb3270c..7e355c4 100644
--- a/ws.c
+++ b/ws.c
@@ -74,14 +74,14 @@ unsigned parse_whitespace_rule(const char *string)
 unsigned whitespace_rule(const char *pathname)
 {
 	static struct git_attr_check *attr_whitespace_rule;
+	struct git_attr_result result[1];
 
-	if (!attr_whitespace_rule)
-		attr_whitespace_rule = git_attr_check_initl("whitespace", NULL);
+	git_attr_check_initl(&attr_whitespace_rule, "whitespace", NULL);
 
-	if (!git_check_attr(pathname, attr_whitespace_rule)) {
+	if (!git_check_attr(pathname, attr_whitespace_rule, result)) {
 		const char *value;
 
-		value = attr_whitespace_rule->check[0].value;
+		value = result[0].value;
 		if (ATTR_TRUE(value)) {
 			/* true (whitespace) */
 			unsigned all_rule = ws_tab_width(whitespace_rule_cfg);
-- 
2.10.1.469.g00a8914

[PATCH 27/35] attr: keep attr stack for each check

[Stefan Beller]

Instead of having a global attr stack, attach the stack to each check.
This allows to use the attr in a multithreaded way.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 attr.c    | 101 +++++++++++++++++++++++++++++++++++++++-----------------------
 attr.h    |   4 ++-
 hashmap.h |   2 ++
 3 files changed, 69 insertions(+), 38 deletions(-)

diff --git a/attr.c b/attr.c
index 32ec453..979bd3c 100644
--- a/attr.c
+++ b/attr.c
@@ -375,15 +375,17 @@ static struct match_attr *parse_attr_line(const char *line, const char *src,
  * .gitignore file and info/excludes file as a fallback.
  */
 
-/* NEEDSWORK: This will become per git_attr_check */
-static struct attr_stack {
+struct attr_stack {
 	struct attr_stack *prev;
 	char *origin;
 	size_t originlen;
 	unsigned num_matches;
 	unsigned alloc;
 	struct match_attr **attrs;
-} *attr_stack;
+};
+
+static struct hashmap all_attr_stacks;
+static int all_attr_stacks_init;
 
 static void free_attr_elem(struct attr_stack *e)
 {
@@ -564,11 +566,23 @@ static void debug_set(const char *what, const char *match, struct git_attr *attr
 
 static void drop_attr_stack(void)
 {
-	while (attr_stack) {
-		struct attr_stack *elem = attr_stack;
-		attr_stack = elem->prev;
-		free_attr_elem(elem);
+	struct hashmap_iter iter;
+	struct git_attr_check *check;
+
+	attr_lock();
+	if (!all_attr_stacks_init) {
+		attr_unlock();
+		return;
 	}
+	hashmap_iter_init(&all_attr_stacks, &iter);
+	while ((check = hashmap_iter_next(&iter))) {
+		while (check->attr_stack) {
+			struct attr_stack *elem = check->attr_stack;
+			check->attr_stack = elem->prev;
+			free_attr_elem(elem);
+		}
+	}
+	attr_unlock();
 }
 
 static const char *git_etc_gitattributes(void)
@@ -598,40 +612,42 @@ static void push_stack(struct attr_stack **attr_stack_p,
 	}
 }
 
-static void bootstrap_attr_stack(void)
+static void bootstrap_attr_stack(struct git_attr_check *check)
 {
 	struct attr_stack *elem;
 
-	if (attr_stack)
+	if (check->attr_stack)
 		return;
 
-	push_stack(&attr_stack, read_attr_from_array(builtin_attr), NULL, 0);
+	push_stack(&check->attr_stack,
+		   read_attr_from_array(builtin_attr), NULL, 0);
 
 	if (git_attr_system())
-		push_stack(&attr_stack,
+		push_stack(&check->attr_stack,
 			   read_attr_from_file(git_etc_gitattributes(), 1),
 			   NULL, 0);
 
 	if (!git_attributes_file)
 		git_attributes_file = xdg_config_home("attributes");
 	if (git_attributes_file)
-		push_stack(&attr_stack,
+		push_stack(&check->attr_stack,
 			   read_attr_from_file(git_attributes_file, 1),
 			   NULL, 0);
 
 	if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
 		elem = read_attr(GITATTRIBUTES_FILE, 1);
-		push_stack(&attr_stack, elem, xstrdup(""), 0);
+		push_stack(&check->attr_stack, elem, xstrdup(""), 0);
 		debug_push(elem);
 	}
 
 	elem = read_attr_from_file(git_path_info_attributes(), 1);
 	if (!elem)
 		elem = xcalloc(1, sizeof(*elem));
-	push_stack(&attr_stack, elem, NULL, 0);
+	push_stack(&check->attr_stack, elem, NULL, 0);
 }
 
-static void prepare_attr_stack(const char *path, int dirlen)
+static void prepare_attr_stack(const char *path, int dirlen,
+			       struct git_attr_check *check)
 {
 	struct attr_stack *elem, *info;
 	const char *cp;
@@ -651,13 +667,13 @@ static void prepare_attr_stack(const char *path, int dirlen)
 	 * .gitattributes in deeper directories to shallower ones,
 	 * and finally use the built-in set as the default.
 	 */
-	bootstrap_attr_stack();
+	bootstrap_attr_stack(check);
 
 	/*
 	 * Pop the "info" one that is always at the top of the stack.
 	 */
-	info = attr_stack;
-	attr_stack = info->prev;
+	info = check->attr_stack;
+	check->attr_stack = info->prev;
 
 	/*
 	 * Pop the ones from directories that are not the prefix of
@@ -665,17 +681,17 @@ static void prepare_attr_stack(const char *path, int dirlen)
 	 * the root one (whose origin is an empty string "") or the builtin
 	 * one (whose origin is NULL) without popping it.
 	 */
-	while (attr_stack->origin) {
-		int namelen = strlen(attr_stack->origin);
+	while (check->attr_stack->origin) {
+		int namelen = strlen(check->attr_stack->origin);
 
-		elem = attr_stack;
+		elem = check->attr_stack;
 		if (namelen <= dirlen &&
 		    !strncmp(elem->origin, path, namelen) &&
 		    (!namelen || path[namelen] == '/'))
 			break;
 
 		debug_pop(elem);
-		attr_stack = elem->prev;
+		check->attr_stack = elem->prev;
 		free_attr_elem(elem);
 	}
 
@@ -691,9 +707,9 @@ static void prepare_attr_stack(const char *path, int dirlen)
 		 */
 		struct strbuf pathbuf = STRBUF_INIT;
 
-		assert(attr_stack->origin);
+		assert(check->attr_stack->origin);
 		while (1) {
-			size_t len = strlen(attr_stack->origin);
+			size_t len = strlen(check->attr_stack->origin);
 			char *origin;
 
 			if (dirlen <= len)
@@ -707,7 +723,7 @@ static void prepare_attr_stack(const char *path, int dirlen)
 			elem = read_attr(pathbuf.buf, 0);
 			strbuf_setlen(&pathbuf, cp - path);
 			origin = strbuf_detach(&pathbuf, &len);
-			push_stack(&attr_stack, elem, origin, len);
+			push_stack(&check->attr_stack, elem, origin, len);
 			debug_push(elem);
 		}
 
@@ -717,7 +733,13 @@ static void prepare_attr_stack(const char *path, int dirlen)
 	/*
 	 * Finally push the "info" one at the top of the stack.
 	 */
-	push_stack(&attr_stack, info, NULL, 0);
+	push_stack(&check->attr_stack, info, NULL, 0);
+	if (!all_attr_stacks_init) {
+		hashmap_init(&all_attr_stacks, NULL, 0);
+		all_attr_stacks_init = 1;
+	}
+	if (!hashmap_get(&all_attr_stacks, check, NULL))
+		hashmap_put(&all_attr_stacks, check);
 }
 
 static int path_matches(const char *pathname, int pathlen,
@@ -743,9 +765,10 @@ static int path_matches(const char *pathname, int pathlen,
 			      pattern, prefix, pat->patternlen, pat->flags);
 }
 
-static int macroexpand_one(int attr_nr, int rem);
+static int macroexpand_one(int attr_nr, int rem, struct git_attr_check *check);
 
-static int fill_one(const char *what, struct match_attr *a, int rem)
+static int fill_one(const char *what, struct match_attr *a, int rem,
+		    struct git_attr_check *check)
 {
 	struct git_attr_check_elem *celem = check_all_attr;
 	int i;
@@ -761,14 +784,14 @@ static int fill_one(const char *what, struct match_attr *a, int rem)
 				  attr, v);
 			*n = v;
 			rem--;
-			rem = macroexpand_one(attr->attr_nr, rem);
+			rem = macroexpand_one(attr->attr_nr, rem, check);
 		}
 	}
 	return rem;
 }
 
 static int fill(const char *path, int pathlen, int basename_offset,
-		struct attr_stack *stk, int rem)
+		struct attr_stack *stk, int rem, struct git_attr_check *check)
 {
 	int i;
 	const char *base = stk->origin ? stk->origin : "";
@@ -779,12 +802,12 @@ static int fill(const char *path, int pathlen, int basename_offset,
 			continue;
 		if (path_matches(path, pathlen, basename_offset,
 				 &a->u.pat, base, stk->originlen))
-			rem = fill_one("fill", a, rem);
+			rem = fill_one("fill", a, rem, check);
 	}
 	return rem;
 }
 
-static int macroexpand_one(int nr, int rem)
+static int macroexpand_one(int nr, int rem, struct git_attr_check *check)
 {
 	struct attr_stack *stk;
 	int i;
@@ -793,13 +816,13 @@ static int macroexpand_one(int nr, int rem)
 	    !check_all_attr[nr].attr->maybe_macro)
 		return rem;
 
-	for (stk = attr_stack; stk; stk = stk->prev) {
+	for (stk = check->attr_stack; stk; stk = stk->prev) {
 		for (i = stk->num_matches - 1; 0 <= i; i--) {
 			struct match_attr *ma = stk->attrs[i];
 			if (!ma->is_macro)
 				continue;
 			if (ma->u.attr->attr_nr == nr)
-				return fill_one("expand", ma, rem);
+				return fill_one("expand", ma, rem, check);
 		}
 	}
 
@@ -848,7 +871,7 @@ static void collect_some_attrs(const char *path, int pathlen,
 		dirlen = 0;
 	}
 
-	prepare_attr_stack(path, dirlen);
+	prepare_attr_stack(path, dirlen, check);
 
 	for (i = 0; i < attr_nr; i++)
 		check_all_attr[i].value = ATTR__UNKNOWN;
@@ -868,8 +891,8 @@ static void collect_some_attrs(const char *path, int pathlen,
 	}
 
 	rem = attr_nr;
-	for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
-		rem = fill(path, pathlen, basename_offset, stk, rem);
+	for (stk = check->attr_stack; 0 < rem && stk; stk = stk->prev)
+		rem = fill(path, pathlen, basename_offset, stk, rem, check);
 
 	if (collect_all) {
 		int check_nr = 0, check_alloc = 0;
@@ -902,6 +925,8 @@ static int git_check_attrs(const char *path, int pathlen,
 {
 	int i;
 
+	attr_lock();
+
 	collect_some_attrs(path, pathlen, check, &result, 0);
 
 	for (i = 0; i < check->check_nr; i++) {
@@ -911,6 +936,8 @@ static int git_check_attrs(const char *path, int pathlen,
 		result[i].value = value;
 	}
 
+	attr_unlock();
+
 	return 0;
 }
 
diff --git a/attr.h b/attr.h
index 1a50288..ab381ae 100644
--- a/attr.h
+++ b/attr.h
@@ -30,12 +30,14 @@ extern const char git_attr__false[];
 #define ATTR_UNSET(v) ((v) == NULL)
 
 struct git_attr_check {
+	struct hashmap_entry entry;
 	int finalized;
 	int check_nr;
 	int check_alloc;
 	const struct git_attr **attr;
+	struct attr_stack *attr_stack;
 };
-#define GIT_ATTR_CHECK_INIT {0, 0, 0, NULL}
+#define GIT_ATTR_CHECK_INIT {HASHMAP_ENTRY_INIT, 0, 0, 0, NULL, NULL}
 
 struct git_attr_result {
 	const char *value;
diff --git a/hashmap.h b/hashmap.h
index ab7958a..d247c62 100644
--- a/hashmap.h
+++ b/hashmap.h
@@ -31,6 +31,8 @@ struct hashmap_entry {
 	unsigned int hash;
 };
 
+#define HASHMAP_ENTRY_INIT {NULL, 0}
+
 typedef int (*hashmap_cmp_fn)(const void *entry, const void *entry_or_key,
 		const void *keydata);
 
-- 
2.10.1.469.g00a8914

[PATCH 28/35] Documentation: fix a typo

[Stefan Beller]

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/gitattributes.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/gitattributes.txt b/Documentation/gitattributes.txt
index 8a061af..5b31797 100644
--- a/Documentation/gitattributes.txt
+++ b/Documentation/gitattributes.txt
@@ -88,7 +88,7 @@ is either not set or empty, $HOME/.config/git/attributes is used instead.
 Attributes for all users on a system should be placed in the
 `$(prefix)/etc/gitattributes` file.
 
-Sometimes you would need to override an setting of an attribute
+Sometimes you would need to override a setting of an attribute
 for a path to `Unspecified` state.  This can be done by listing
 the name of the attribute prefixed with an exclamation point `!`.
 
-- 
2.10.1.469.g00a8914

[PATCH 29/35] pathspec: move long magic parsing out of prefix_pathspec

[Stefan Beller]

`prefix_pathspec` is quite a lengthy function and we plan on adding more.
Split it up for better readability. As we want to add code into the
inner loop of the long magic parsing, we also benefit from lower
indentation.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 pathspec.c | 84 +++++++++++++++++++++++++++++++++++---------------------------
 1 file changed, 47 insertions(+), 37 deletions(-)

diff --git a/pathspec.c b/pathspec.c
index 86f2b44..67678fc 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -88,6 +88,52 @@ static void prefix_short_magic(struct strbuf *sb, int prefixlen,
 	strbuf_addf(sb, ",prefix:%d)", prefixlen);
 }
 
+static void eat_long_magic(struct pathspec_item *item, const char *elt,
+		unsigned *magic, int *pathspec_prefix,
+		const char **copyfrom_, const char **long_magic_end)
+{
+	int i;
+	const char *copyfrom = *copyfrom_;
+	/* longhand */
+	const char *nextat;
+	for (copyfrom = elt + 2;
+	     *copyfrom && *copyfrom != ')';
+	     copyfrom = nextat) {
+		size_t len = strcspn(copyfrom, ",)");
+		if (copyfrom[len] == ',')
+			nextat = copyfrom + len + 1;
+		else
+			/* handle ')' and '\0' */
+			nextat = copyfrom + len;
+		if (!len)
+			continue;
+		for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
+			if (strlen(pathspec_magic[i].name) == len &&
+			    !strncmp(pathspec_magic[i].name, copyfrom, len)) {
+				*magic |= pathspec_magic[i].bit;
+				break;
+			}
+			if (starts_with(copyfrom, "prefix:")) {
+				char *endptr;
+				*pathspec_prefix = strtol(copyfrom + 7,
+							  &endptr, 10);
+				if (endptr - copyfrom != len)
+					die(_("invalid parameter for pathspec magic 'prefix'"));
+				/* "i" would be wrong, but it does not matter */
+				break;
+			}
+		}
+		if (ARRAY_SIZE(pathspec_magic) <= i)
+			die(_("Invalid pathspec magic '%.*s' in '%s'"),
+			    (int) len, copyfrom, elt);
+	}
+	if (*copyfrom != ')')
+		die(_("Missing ')' at the end of pathspec magic in '%s'"), elt);
+	*long_magic_end = copyfrom;
+	copyfrom++;
+	*copyfrom_ = copyfrom;
+}
+
 /*
  * Take an element of a pathspec and check for magic signatures.
  * Append the result to the prefix. Return the magic bitmap.
@@ -150,43 +196,7 @@ static unsigned prefix_pathspec(struct pathspec_item *item,
 	    (flags & PATHSPEC_LITERAL_PATH)) {
 		; /* nothing to do */
 	} else if (elt[1] == '(') {
-		/* longhand */
-		const char *nextat;
-		for (copyfrom = elt + 2;
-		     *copyfrom && *copyfrom != ')';
-		     copyfrom = nextat) {
-			size_t len = strcspn(copyfrom, ",)");
-			if (copyfrom[len] == ',')
-				nextat = copyfrom + len + 1;
-			else
-				/* handle ')' and '\0' */
-				nextat = copyfrom + len;
-			if (!len)
-				continue;
-			for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
-				if (strlen(pathspec_magic[i].name) == len &&
-				    !strncmp(pathspec_magic[i].name, copyfrom, len)) {
-					magic |= pathspec_magic[i].bit;
-					break;
-				}
-				if (starts_with(copyfrom, "prefix:")) {
-					char *endptr;
-					pathspec_prefix = strtol(copyfrom + 7,
-								 &endptr, 10);
-					if (endptr - copyfrom != len)
-						die(_("invalid parameter for pathspec magic 'prefix'"));
-					/* "i" would be wrong, but it does not matter */
-					break;
-				}
-			}
-			if (ARRAY_SIZE(pathspec_magic) <= i)
-				die(_("Invalid pathspec magic '%.*s' in '%s'"),
-				    (int) len, copyfrom, elt);
-		}
-		if (*copyfrom != ')')
-			die(_("Missing ')' at the end of pathspec magic in '%s'"), elt);
-		long_magic_end = copyfrom;
-		copyfrom++;
+		eat_long_magic(item, elt, &magic, &pathspec_prefix, &copyfrom, &long_magic_end);
 	} else {
 		/* shorthand */
 		for (copyfrom = elt + 1;
-- 
2.10.1.469.g00a8914

[PATCH 30/35] pathspec: move prefix check out of the inner loop

[Stefan Beller]

The prefix check is not related the check of pathspec magic; also there
is no code that is relevant after we'd break the loop on a match for
"prefix:". So move the check before the loop and shortcircuit the outer
loop.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 pathspec.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/pathspec.c b/pathspec.c
index 67678fc..d44f8e7 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -107,21 +107,22 @@ static void eat_long_magic(struct pathspec_item *item, const char *elt,
 			nextat = copyfrom + len;
 		if (!len)
 			continue;
+
+		if (starts_with(copyfrom, "prefix:")) {
+			char *endptr;
+			*pathspec_prefix = strtol(copyfrom + 7,
+						  &endptr, 10);
+			if (endptr - copyfrom != len)
+				die(_("invalid parameter for pathspec magic 'prefix'"));
+			continue;
+		}
+
 		for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
 			if (strlen(pathspec_magic[i].name) == len &&
 			    !strncmp(pathspec_magic[i].name, copyfrom, len)) {
 				*magic |= pathspec_magic[i].bit;
 				break;
 			}
-			if (starts_with(copyfrom, "prefix:")) {
-				char *endptr;
-				*pathspec_prefix = strtol(copyfrom + 7,
-							  &endptr, 10);
-				if (endptr - copyfrom != len)
-					die(_("invalid parameter for pathspec magic 'prefix'"));
-				/* "i" would be wrong, but it does not matter */
-				break;
-			}
 		}
 		if (ARRAY_SIZE(pathspec_magic) <= i)
 			die(_("Invalid pathspec magic '%.*s' in '%s'"),
-- 
2.10.1.469.g00a8914

[PATCH 31/35] pathspec: allow querying for attributes

[Stefan Beller]

The pathspec mechanism is extended via the new
":(attr:eol=input)pattern/to/match" syntax to filter paths so that it
requires paths to not just match the given pattern but also have the
specified attrs attached for them to be chosen.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/glossary-content.txt |  20 ++++
 dir.c                              |  41 +++++++-
 pathspec.c                         | 106 +++++++++++++++++++-
 pathspec.h                         |  19 +++-
 t/t6134-pathspec-with-labels.sh    | 191 +++++++++++++++++++++++++++++++++++++
 5 files changed, 370 insertions(+), 7 deletions(-)
 create mode 100755 t/t6134-pathspec-with-labels.sh

diff --git a/Documentation/glossary-content.txt b/Documentation/glossary-content.txt
index 8ad29e6..f90bd45 100644
--- a/Documentation/glossary-content.txt
+++ b/Documentation/glossary-content.txt
@@ -384,6 +384,26 @@ full pathname may have special meaning:
 +
 Glob magic is incompatible with literal magic.
 
+attr;;
+After `attr:` comes a space separated list of "attribute
+requirements", all of which must be met in order for the
+path to be considered a match; this is in addition to the
+usual non-magic pathspec pattern matching.
++
+Each of the attribute requirements for the path takes one of
+these forms:
+
+- "`ATTR`" requires that the attribute `ATTR` must be set.
+
+- "`-ATTR`" requires that the attribute `ATTR` must be unset.
+
+- "`ATTR=VALUE`" requires that the attribute `ATTR` must be
+  set to the string `VALUE`.
+
+- "`!ATTR`" requires that the attribute `ATTR` must be
+  unspecified.
++
+
 exclude;;
 	After a path matches any non-exclude pathspec, it will be run
 	through all exclude pathspec (magic signature: `!`). If it
diff --git a/dir.c b/dir.c
index 3bad1ad..c56d2ee 100644
--- a/dir.c
+++ b/dir.c
@@ -9,6 +9,7 @@
  */
 #include "cache.h"
 #include "dir.h"
+#include "attr.h"
 #include "refs.h"
 #include "wildmatch.h"
 #include "pathspec.h"
@@ -139,7 +140,8 @@ static size_t common_prefix_len(const struct pathspec *pathspec)
 		       PATHSPEC_LITERAL |
 		       PATHSPEC_GLOB |
 		       PATHSPEC_ICASE |
-		       PATHSPEC_EXCLUDE);
+		       PATHSPEC_EXCLUDE |
+		       PATHSPEC_ATTR);
 
 	for (n = 0; n < pathspec->nr; n++) {
 		size_t i = 0, len = 0, item_len;
@@ -207,6 +209,37 @@ int within_depth(const char *name, int namelen,
 	return 1;
 }
 
+static int match_attrs(const char *name, int namelen,
+		       const struct pathspec_item *item)
+{
+	int i;
+	struct git_attr_result *res = git_attr_result_alloc(item->attr_check);
+
+	git_check_attr(name, item->attr_check, res);
+	for (i = 0; i < item->attr_match_nr; i++) {
+		const char *value;
+		int matched;
+		enum attr_match_mode match_mode;
+
+		value = res[i].value;
+		match_mode = item->attr_match[i].match_mode;
+
+		if (ATTR_TRUE(value))
+			matched = (match_mode == MATCH_SET);
+		else if (ATTR_FALSE(value))
+			matched = (match_mode == MATCH_UNSET);
+		else if (ATTR_UNSET(value))
+			matched = (match_mode == MATCH_UNSPECIFIED);
+		else
+			matched = (match_mode == MATCH_VALUE &&
+				   !strcmp(item->attr_match[i].value, value));
+		if (!matched)
+			return 0;
+	}
+
+	return 1;
+}
+
 #define DO_MATCH_EXCLUDE   1
 #define DO_MATCH_DIRECTORY 2
 
@@ -262,6 +295,9 @@ static int match_pathspec_item(const struct pathspec_item *item, int prefix,
 	    strncmp(item->match, name - prefix, item->prefix))
 		return 0;
 
+	if (item->attr_match_nr && !match_attrs(name, namelen, item))
+		return 0;
+
 	/* If the match was just the prefix, we matched */
 	if (!*match)
 		return MATCHED_RECURSIVELY;
@@ -314,7 +350,8 @@ static int do_match_pathspec(const struct pathspec *ps,
 		       PATHSPEC_LITERAL |
 		       PATHSPEC_GLOB |
 		       PATHSPEC_ICASE |
-		       PATHSPEC_EXCLUDE);
+		       PATHSPEC_EXCLUDE |
+		       PATHSPEC_ATTR);
 
 	if (!ps->nr) {
 		if (!ps->recursive ||
diff --git a/pathspec.c b/pathspec.c
index d44f8e7..4aa7ea5 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -1,6 +1,8 @@
 #include "cache.h"
 #include "dir.h"
 #include "pathspec.h"
+#include "attr.h"
+#include "argv-array.h"
 
 /*
  * Finds which of the given pathspecs match items in the index.
@@ -88,12 +90,79 @@ static void prefix_short_magic(struct strbuf *sb, int prefixlen,
 	strbuf_addf(sb, ",prefix:%d)", prefixlen);
 }
 
+static void parse_pathspec_attr_match(struct pathspec_item *item, const char *value)
+{
+	struct string_list_item *si;
+	struct string_list list = STRING_LIST_INIT_DUP;
+	struct argv_array attrs = ARGV_ARRAY_INIT;
+
+
+	if (!value || !strlen(value))
+		die(_("attr spec must not be empty"));
+
+	string_list_split(&list, value, ' ', -1);
+	string_list_remove_empty_items(&list, 0);
+
+	ALLOC_GROW(item->attr_match, item->attr_match_nr + list.nr, item->attr_match_alloc);
+
+	for_each_string_list_item(si, &list) {
+		size_t attr_len;
+
+		int j = item->attr_match_nr++;
+		const char *attr = si->string;
+		struct attr_match *am = &item->attr_match[j];
+
+		switch (*attr) {
+		case '!':
+			am->match_mode = MATCH_UNSPECIFIED;
+			attr++;
+			attr_len = strlen(attr);
+			break;
+		case '-':
+			am->match_mode = MATCH_UNSET;
+			attr++;
+			attr_len = strlen(attr);
+			break;
+		default:
+			attr_len = strcspn(attr, "=");
+			if (attr[attr_len] != '=')
+				am->match_mode = MATCH_SET;
+			else {
+				am->match_mode = MATCH_VALUE;
+				am->value = xstrdup(&attr[attr_len + 1]);
+				if (strchr(am->value, '\\'))
+					die(_("attr spec values must not contain backslashes"));
+			}
+			break;
+		}
+
+		if (!attr_name_valid(attr, attr_len)) {
+			struct strbuf sb = STRBUF_INIT;
+			am->match_mode = INVALID_ATTR;
+			invalid_attr_name_message(&sb, attr, attr_len);
+			die(_("invalid attribute in '%s': '%s'"), value, sb.buf);
+		}
+
+		argv_array_push(&attrs, xmemdupz(attr, attr_len));
+	}
+
+	if (!item->attr_check)
+		git_attr_check_initv(&item->attr_check, attrs.argv);
+	else
+		die(_("Only one 'attr:' specification is allowed."));
+
+	argv_array_clear(&attrs);
+	string_list_clear(&list, 0);
+	return;
+}
+
 static void eat_long_magic(struct pathspec_item *item, const char *elt,
 		unsigned *magic, int *pathspec_prefix,
 		const char **copyfrom_, const char **long_magic_end)
 {
 	int i;
 	const char *copyfrom = *copyfrom_;
+	const char *body;
 	/* longhand */
 	const char *nextat;
 	for (copyfrom = elt + 2;
@@ -108,15 +177,22 @@ static void eat_long_magic(struct pathspec_item *item, const char *elt,
 		if (!len)
 			continue;
 
-		if (starts_with(copyfrom, "prefix:")) {
+		if (skip_prefix(copyfrom, "prefix:", &body)) {
 			char *endptr;
-			*pathspec_prefix = strtol(copyfrom + 7,
-						  &endptr, 10);
+			*pathspec_prefix = strtol(body, &endptr, 10);
 			if (endptr - copyfrom != len)
 				die(_("invalid parameter for pathspec magic 'prefix'"));
 			continue;
 		}
 
+		if (skip_prefix(copyfrom, "attr:", &body)) {
+			char *attr_body = xmemdupz(body, len - strlen("attr:"));
+			parse_pathspec_attr_match(item, attr_body);
+			free(attr_body);
+			*magic |= PATHSPEC_ATTR;
+			continue;
+		}
+
 		for (i = 0; i < ARRAY_SIZE(pathspec_magic); i++) {
 			if (strlen(pathspec_magic[i].name) == len &&
 			    !strncmp(pathspec_magic[i].name, copyfrom, len)) {
@@ -425,7 +501,10 @@ void parse_pathspec(struct pathspec *pathspec,
 	for (i = 0; i < n; i++) {
 		unsigned short_magic;
 		entry = argv[i];
-
+		item[i].attr_check = NULL;
+		item[i].attr_match = NULL;
+		item[i].attr_match_nr = 0;
+		item[i].attr_match_alloc = 0;
 		item[i].magic = prefix_pathspec(item + i, &short_magic,
 						argv + i, flags,
 						prefix, prefixlen, entry);
@@ -447,6 +526,13 @@ void parse_pathspec(struct pathspec *pathspec,
 		if (item[i].nowildcard_len < item[i].len)
 			pathspec->has_wildcard = 1;
 		pathspec->magic |= item[i].magic;
+
+		if (item[i].attr_match_nr) {
+			int j;
+			for (j = 0; j < item[i].attr_match_nr; j++)
+				if (item[i].attr_match[j].match_mode == INVALID_ATTR)
+					die(_("attribute spec in the wrong syntax are prohibited."));
+		}
 	}
 
 	if (nr_exclude == n)
@@ -500,6 +586,18 @@ void copy_pathspec(struct pathspec *dst, const struct pathspec *src)
 
 void clear_pathspec(struct pathspec *pathspec)
 {
+	int i, j;
+	for (i = 0; i < pathspec->nr; i++) {
+		if (!pathspec->items[i].attr_match_nr)
+			continue;
+		for (j = 0; j < pathspec->items[j].attr_match_nr; j++)
+			free(pathspec->items[i].attr_match[j].value);
+		free(pathspec->items[i].attr_match);
+		if (pathspec->items[i].attr_check)
+			git_attr_check_clear(pathspec->items[i].attr_check);
+		free(pathspec->items[i].attr_check);
+	}
+
 	free(pathspec->items);
 	pathspec->items = NULL;
 }
diff --git a/pathspec.h b/pathspec.h
index 59809e4..c2d046d 100644
--- a/pathspec.h
+++ b/pathspec.h
@@ -8,13 +8,15 @@
 #define PATHSPEC_GLOB		(1<<3)
 #define PATHSPEC_ICASE		(1<<4)
 #define PATHSPEC_EXCLUDE	(1<<5)
+#define PATHSPEC_ATTR		(1<<6)
 #define PATHSPEC_ALL_MAGIC	  \
 	(PATHSPEC_FROMTOP	| \
 	 PATHSPEC_MAXDEPTH	| \
 	 PATHSPEC_LITERAL	| \
 	 PATHSPEC_GLOB		| \
 	 PATHSPEC_ICASE		| \
-	 PATHSPEC_EXCLUDE)
+	 PATHSPEC_EXCLUDE	| \
+	 PATHSPEC_ATTR)
 
 #define PATHSPEC_ONESTAR 1	/* the pathspec pattern satisfies GFNM_ONESTAR */
 
@@ -32,6 +34,21 @@ struct pathspec {
 		int len, prefix;
 		int nowildcard_len;
 		int flags;
+		int attr_match_nr;
+		int attr_match_alloc;
+		struct attr_match {
+			char *value;
+			enum attr_match_mode {
+				MATCH_SET,
+				MATCH_UNSET,
+				MATCH_VALUE,
+				MATCH_UNSPECIFIED,
+				MATCH_NOT_UNSPECIFIED,
+				MATCH_SET_OR_VALUE,
+				INVALID_ATTR
+			} match_mode;
+		} *attr_match;
+		struct git_attr_check *attr_check;
 	} *items;
 };
 
diff --git a/t/t6134-pathspec-with-labels.sh b/t/t6134-pathspec-with-labels.sh
new file mode 100755
index 0000000..e276811
--- /dev/null
+++ b/t/t6134-pathspec-with-labels.sh
@@ -0,0 +1,191 @@
+#!/bin/sh
+
+test_description='test labels in pathspecs'
+. ./test-lib.sh
+
+test_expect_success 'setup a tree' '
+	cat <<-EOF >expect &&
+	fileA
+	fileAB
+	fileAC
+	fileB
+	fileBC
+	fileC
+	fileNoLabel
+	fileSetLabel
+	fileUnsetLabel
+	fileValue
+	fileWrongLabel
+	sub/fileA
+	sub/fileAB
+	sub/fileAC
+	sub/fileB
+	sub/fileBC
+	sub/fileC
+	sub/fileNoLabel
+	sub/fileSetLabel
+	sub/fileUnsetLabel
+	sub/fileValue
+	sub/fileWrongLabel
+	EOF
+	mkdir sub &&
+	while read path
+	do
+		: >$path &&
+		git add $path || return 1
+	done <expect &&
+	git commit -m "initial commit" &&
+	git ls-files >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'pathspec with no attr' '
+	test_must_fail git ls-files ":(attr:)"
+'
+
+test_expect_success 'pathspec with labels and non existent .gitattributes' '
+	git ls-files ":(attr:label)" >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_success 'setup .gitattributes' '
+	cat <<-EOF >.gitattributes &&
+	fileA labelA
+	fileB labelB
+	fileC labelC
+	fileAB labelA labelB
+	fileAC labelA labelC
+	fileBC labelB labelC
+	fileUnsetLabel -label
+	fileSetLabel label
+	fileValue label=foo
+	fileWrongLabel label☺
+	EOF
+	git add .gitattributes &&
+	git commit -m "add attributes"
+'
+
+test_expect_success 'check specific set attr' '
+	cat <<-EOF >expect &&
+	fileSetLabel
+	sub/fileSetLabel
+	EOF
+	git ls-files ":(attr:label)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check specific unset attr' '
+	cat <<-EOF >expect &&
+	fileUnsetLabel
+	sub/fileUnsetLabel
+	EOF
+	git ls-files ":(attr:-label)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check specific value attr' '
+	cat <<-EOF >expect &&
+	fileValue
+	sub/fileValue
+	EOF
+	git ls-files ":(attr:label=foo)" >actual &&
+	test_cmp expect actual &&
+	git ls-files ":(attr:label=bar)" >actual &&
+	test_must_be_empty actual
+'
+
+test_expect_success 'check unspecified attr' '
+	cat <<-EOF >expect &&
+	.gitattributes
+	fileA
+	fileAB
+	fileAC
+	fileB
+	fileBC
+	fileC
+	fileNoLabel
+	fileWrongLabel
+	sub/fileA
+	sub/fileAB
+	sub/fileAC
+	sub/fileB
+	sub/fileBC
+	sub/fileC
+	sub/fileNoLabel
+	sub/fileWrongLabel
+	EOF
+	git ls-files ":(attr:!label)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check multiple unspecified attr' '
+	cat <<-EOF >expect &&
+	.gitattributes
+	fileC
+	fileNoLabel
+	fileWrongLabel
+	sub/fileC
+	sub/fileNoLabel
+	sub/fileWrongLabel
+	EOF
+	git ls-files ":(attr:!labelB !labelA !label)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check label with more labels but excluded path' '
+	cat <<-EOF >expect &&
+	fileAB
+	fileB
+	fileBC
+	EOF
+	git ls-files ":(attr:labelB)" ":(exclude)sub/" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'check label excluding other labels' '
+	cat <<-EOF >expect &&
+	fileAB
+	fileB
+	fileBC
+	sub/fileAB
+	sub/fileB
+	EOF
+	git ls-files ":(attr:labelB)" ":(exclude,attr:labelC)sub/" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'fail on multiple attr specifiers in one pathspec item' '
+	test_must_fail git ls-files . ":(attr:labelB,attr:labelC)" 2>actual &&
+	test_i18ngrep "Only one" actual
+'
+
+test_expect_success 'checking attributes in a multithreaded process' '
+	cat <<-EOF >expect &&
+	fileA:A
+	EOF
+	echo A >fileA &&
+	echo A >fileB &&
+	git grep A -- ":(attr:labelA)" >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'fail if attr magic is used places not implemented' '
+	# The main purpose of this test is to check that we actually fail
+	# when you attempt to use attr magic in commands that do not implement
+	# attr magic. This test does not advocate git-add to stay that way,
+	# though, but git-add is convenient as it has its own internal pathspec
+	# parsing.
+	test_must_fail git add ":(attr:labelB)" 2>actual &&
+	test_i18ngrep "unsupported magic" actual
+'
+
+test_expect_success 'abort on giving invalid label on the command line' '
+	test_must_fail git ls-files . ":(attr:☺)"
+'
+
+test_expect_success 'abort on asking for wrong magic' '
+	test_must_fail git ls-files . ":(attr:-label=foo)" &&
+	test_must_fail git ls-files . ":(attr:!label=foo)"
+'
+
+test_done
-- 
2.10.1.469.g00a8914

[PATCH 32/35] pathspec: allow escaped query values

[Stefan Beller]

In our own .gitattributes file we have attributes such as:

    *.[ch] whitespace=indent,trail,space

When querying for attributes we want to be able to ask for the exact
value, i.e.

    git ls-files :(attr:whitespace=indent,trail,space)

should work, but the commas are used in the attr magic to introduce
the next attr, such that this query currently fails with

fatal: Invalid pathspec magic 'trail' in ':(attr:whitespace=indent,trail,space)'

This change allows escaping characters by a backslash, such that the query

    git ls-files :(attr:whitespace=indent\,trail\,space)

will match all path that have the value "indent,trail,space" for the
whitespace attribute. To accomplish this, we need to modify two places.
First `eat_long_magic` needs to not stop early upon seeing a comma or
closing paren that is escaped. As a second step we need to remove any
escaping from the attr value.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 pathspec.c                      | 53 +++++++++++++++++++++++++++++++++++++----
 t/t6134-pathspec-with-labels.sh | 10 ++++++++
 2 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/pathspec.c b/pathspec.c
index 4aa7ea5..d702803 100644
--- a/pathspec.c
+++ b/pathspec.c
@@ -90,13 +90,57 @@ static void prefix_short_magic(struct strbuf *sb, int prefixlen,
 	strbuf_addf(sb, ",prefix:%d)", prefixlen);
 }
 
+static size_t strcspn_escaped(const char *s, const char *stop)
+{
+	const char *i;
+
+	for (i = s; *i; i++) {
+		/* skip the escaped character */
+		if (i[0] == '\\' && i[1]) {
+			i++;
+			continue;
+		}
+
+		if (strchr(stop, *i))
+			break;
+	}
+	return i - s;
+}
+
+static inline int invalid_value_char(const char ch)
+{
+	if (isalnum(ch) || strchr(",-_", ch))
+		return 0;
+	return -1;
+}
+
+static char *attr_value_unescape(const char *value)
+{
+	const char *src;
+	char *dst, *ret;
+
+	ret = xmallocz(strlen(value));
+	for (src = value, dst = ret; *src; src++, dst++) {
+		if (*src == '\\') {
+			if (!src[1])
+				die(_("Escape character '\\' not allowed as "
+				      "last character in attr value"));
+			src++;
+		}
+		if (invalid_value_char(*src))
+			die("cannot use '%c' for value matching", *src);
+		*dst = *src;
+	}
+	*dst = '\0';
+	return ret;
+}
+
 static void parse_pathspec_attr_match(struct pathspec_item *item, const char *value)
 {
 	struct string_list_item *si;
 	struct string_list list = STRING_LIST_INIT_DUP;
 	struct argv_array attrs = ARGV_ARRAY_INIT;
 
-
 	if (!value || !strlen(value))
 		die(_("attr spec must not be empty"));
 
@@ -128,10 +172,9 @@ static void parse_pathspec_attr_match(struct pathspec_item *item, const char *va
 			if (attr[attr_len] != '=')
 				am->match_mode = MATCH_SET;
 			else {
+				const char *v = &attr[attr_len + 1];
 				am->match_mode = MATCH_VALUE;
-				am->value = xstrdup(&attr[attr_len + 1]);
-				if (strchr(am->value, '\\'))
-					die(_("attr spec values must not contain backslashes"));
+				am->value = attr_value_unescape(v);
 			}
 			break;
 		}
@@ -168,7 +211,7 @@ static void eat_long_magic(struct pathspec_item *item, const char *elt,
 	for (copyfrom = elt + 2;
 	     *copyfrom && *copyfrom != ')';
 	     copyfrom = nextat) {
-		size_t len = strcspn(copyfrom, ",)");
+		size_t len = strcspn_escaped(copyfrom, ",)");
 		if (copyfrom[len] == ',')
 			nextat = copyfrom + len + 1;
 		else
diff --git a/t/t6134-pathspec-with-labels.sh b/t/t6134-pathspec-with-labels.sh
index e276811..5aafc0c 100755
--- a/t/t6134-pathspec-with-labels.sh
+++ b/t/t6134-pathspec-with-labels.sh
@@ -188,4 +188,14 @@ test_expect_success 'abort on asking for wrong magic' '
 	test_must_fail git ls-files . ":(attr:!label=foo)"
 '
 
+test_expect_success 'check attribute list' '
+	cat <<-EOF >>.gitattributes &&
+	* whitespace=indent,trail,space
+	EOF
+	cat .gitattributes &&
+	git ls-files ":(attr:whitespace=indent\,trail\,space)" >actual &&
+	git ls-files >expect &&
+	test_cmp expect actual
+'
+
 test_done
-- 
2.10.1.469.g00a8914

[PATCH 33/35] submodule update: add `--init-default-path` switch

[Stefan Beller]

The new switch `--init-default-path` initializes the submodules which are
configured in `submodule.defaultUpdatePath` instead of those given as
command line arguments before updating. In the first implementation this
is made incompatible with further command line arguments as it is
unclear what the user means by

    git submodule update --init --init-default-path <paths>

This new switch allows to record more complex patterns as it saves
retyping them whenever you invoke update.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/config.txt        |  5 ++++
 Documentation/git-submodule.txt | 17 +++++++++----
 git-submodule.sh                | 21 +++++++++++++---
 t/t7400-submodule-basic.sh      | 53 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 89 insertions(+), 7 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index a179474..290de3b 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2885,6 +2885,11 @@ submodule.alternateErrorStrategy
 	as computed via `submodule.alternateLocation`. Possible values are
 	`ignore`, `info`, `die`. Default is `die`.
 
+submodule.defaultUpdatePath::
+	Specifies a set of submodules to initialize when calling
+	`git submodule --init-default-group` by using the pathspec
+	syntax.
+
 tag.forceSignAnnotated::
 	A boolean to specify whether annotated tags created should be GPG signed.
 	If `--annotate` is specified on the command line, it takes
diff --git a/Documentation/git-submodule.txt b/Documentation/git-submodule.txt
index bf3bb37..503fec8 100644
--- a/Documentation/git-submodule.txt
+++ b/Documentation/git-submodule.txt
@@ -14,10 +14,10 @@ SYNOPSIS
 'git submodule' [--quiet] status [--cached] [--recursive] [--] [<path>...]
 'git submodule' [--quiet] init [--] [<path>...]
 'git submodule' [--quiet] deinit [-f|--force] (--all|[--] <path>...)
-'git submodule' [--quiet] update [--init] [--remote] [-N|--no-fetch]
-	      [--[no-]recommend-shallow] [-f|--force] [--rebase|--merge]
-	      [--reference <repository>] [--depth <depth>] [--recursive]
-	      [--jobs <n>] [--] [<path>...]
+'git submodule' [--quiet] update [--init[-default-path]] [--remote] [-N|--no-fetch]
+	      [--[no-]recommend-shallow]
+	      [-f|--force] [--rebase|--merge] [--reference <repository>]
+	      [--depth <depth>] [--recursive] [--jobs <n>] [--] [<path>...]
 'git submodule' [--quiet] summary [--cached|--files] [(-n|--summary-limit) <n>]
 	      [commit] [--] [<path>...]
 'git submodule' [--quiet] foreach [--recursive] <command>
@@ -194,6 +194,10 @@ If the submodule is not yet initialized, and you just want to use the
 setting as stored in .gitmodules, you can automatically initialize the
 submodule with the `--init` option.
 
+You can configure a set of submodules using pathspec syntax in
+submodule.defaultUpdatePath you can use `--init-default-path` to initialize
+those before updating.
+
 If `--recursive` is specified, this command will recurse into the
 registered submodules, and update any nested submodules within.
 --
@@ -361,6 +365,11 @@ the submodule itself.
 	Initialize all submodules for which "git submodule init" has not been
 	called so far before updating.
 
+--init-default-path::
+	This option is only valid for the update command.
+	Initialize all submodules configured in "`submodule.defaultUpdatePath`"
+	that have not been updated before.
+
 --name::
 	This option is only valid for the add command. It sets the submodule's
 	name to the given string instead of defaulting to its path. The name
diff --git a/git-submodule.sh b/git-submodule.sh
index a024a13..334cecc 100755
--- a/git-submodule.sh
+++ b/git-submodule.sh
@@ -9,7 +9,7 @@ USAGE="[--quiet] add [-b <branch>] [-f|--force] [--name <name>] [--reference <re
    or: $dashless [--quiet] status [--cached] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] init [--] [<path>...]
    or: $dashless [--quiet] deinit [-f|--force] (--all| [--] <path>...)
-   or: $dashless [--quiet] update [--init] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--[no-]recommend-shallow] [--reference <repository>] [--recursive] [--] [<path>...]
+   or: $dashless [--quiet] update [--init[-default-path]] [--remote] [-N|--no-fetch] [-f|--force] [--checkout|--merge|--rebase] [--[no-]recommend-shallow] [--reference <repository>] [--recursive] [--] [<path>...]
    or: $dashless [--quiet] summary [--cached|--files] [--summary-limit <n>] [commit] [--] [<path>...]
    or: $dashless [--quiet] foreach [--recursive] <command>
    or: $dashless [--quiet] sync [--recursive] [--] [<path>...]"
@@ -503,7 +503,12 @@ cmd_update()
 			progress="--progress"
 			;;
 		-i|--init)
-			init=1
+			test -z $init || test $init = by_args || die "$(gettext "Only one of --init or --init-default-path may be used.")"
+			init=by_args
+			;;
+		--init-default-path)
+			test -z $init || test $init = by_config || die "$(gettext "Only one of --init or --init-default-path may be used.")"
+			init=by_config
 			;;
 		--remote)
 			remote=1
@@ -572,7 +577,17 @@ cmd_update()
 
 	if test -n "$init"
 	then
-		cmd_init "--" "$@" || return
+		if test "$init" = "by_config"
+		then
+			if test $# -gt 0
+			then
+				die "$(gettext "path arguments are incompatible with --init-default-path")"
+			fi
+			cmd_init "--" $(git config --get-all submodule.defaultUpdatePath) || return
+		else
+			cmd_init "--" "$@" || return
+		fi
+
 	fi
 
 	{
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index b77cce8..4699b1c 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -1116,5 +1116,58 @@ test_expect_success 'submodule helper list is not confused by common prefixes' '
 	test_cmp expect actual
 '
 
+test_expect_success 'setup superproject with submodules' '
+	mkdir sub1 &&
+	(
+		cd sub1 &&
+		git init &&
+		test_commit test &&
+		test_commit test2
+	) &&
+	mkdir multisuper &&
+	(
+		cd multisuper &&
+		git init &&
+		git submodule add ../sub1 sub0 &&
+		git submodule add ../sub1 sub1 &&
+		git submodule add ../sub1 sub2 &&
+		git submodule add ../sub1 sub3 &&
+		git commit -m "add some submodules"
+	)
+'
+
+cat >expect <<-EOF
+-sub0
+ sub1 (test2)
+ sub2 (test2)
+ sub3 (test2)
+EOF
+
+test_expect_success 'submodule update --init with a specification' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	(
+		cd multisuper_clone &&
+		git submodule update --init . ":(exclude)sub0" &&
+		git submodule status |cut -c 1,43- >../actual
+	) &&
+	test_cmp expect actual
+'
+
+test_expect_success 'submodule update --init-default-path' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	pwd=$(pwd) &&
+	git clone file://"$pwd"/multisuper multisuper_clone &&
+	(
+		cd multisuper_clone &&
+		git config submodule.defaultUpdatePath "." &&
+		git config --add submodule.defaultUpdatePath ":(exclude)sub0" &&
+		git submodule update --init-default-path &&
+		git submodule status |cut -c 1,43- >../actual &&
+		test_must_fail git submodule update --init-default-path sub0
+	) &&
+	test_cmp expect actual
+'
 
 test_done
-- 
2.10.1.469.g00a8914

[PATCH 34/35] clone: add --init-submodule=<pathspec> switch

[Stefan Beller]

The new switch passes the pathspec to `git submodule update --init`
which is called after the actual clone is done.

Additionally this configures the submodule.defaultUpdatePath to
be the given pathspec, such that any future invocation of
`git submodule update --init-default-paths` will keep up
with the pathspec.

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 Documentation/config.txt    |  2 +-
 Documentation/git-clone.txt | 23 +++++++++----
 builtin/clone.c             | 36 ++++++++++++++++++--
 t/t7400-submodule-basic.sh  | 81 +++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 132 insertions(+), 10 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 290de3b..917904e 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -2887,7 +2887,7 @@ submodule.alternateErrorStrategy
 
 submodule.defaultUpdatePath::
 	Specifies a set of submodules to initialize when calling
-	`git submodule --init-default-group` by using the pathspec
+	`git submodule --init-default-path` by using the pathspec
 	syntax.
 
 tag.forceSignAnnotated::
diff --git a/Documentation/git-clone.txt b/Documentation/git-clone.txt
index 35cc34b..1089f38 100644
--- a/Documentation/git-clone.txt
+++ b/Documentation/git-clone.txt
@@ -15,7 +15,8 @@ SYNOPSIS
 	  [--dissociate] [--separate-git-dir <git dir>]
 	  [--depth <depth>] [--[no-]single-branch]
 	  [--recursive | --recurse-submodules] [--[no-]shallow-submodules]
-	  [--jobs <n>] [--] <repository> [<directory>]
+	  [--init-submodule <pathspec>] [--jobs <n>] [--]
+	  <repository> [<directory>]
 
 DESCRIPTION
 -----------
@@ -217,12 +218,20 @@ objects from the source repository into a pack in the cloned repository.
 
 --recursive::
 --recurse-submodules::
-	After the clone is created, initialize all submodules within,
-	using their default settings. This is equivalent to running
-	`git submodule update --init --recursive` immediately after
-	the clone is finished. This option is ignored if the cloned
-	repository does not have a worktree/checkout (i.e. if any of
-	`--no-checkout`/`-n`, `--bare`, or `--mirror` is given)
+	After the clone is created, initialize and clone all submodules
+	within, using their default settings. This is equivalent to
+	running `git submodule update --recursive --init `
+	immediately after the clone is finished. This option is ignored
+	if the cloned repository does not have a worktree/checkout (i.e.
+	if any of `--no-checkout`/`-n`, `--bare`, or `--mirror` is given)
+
+--init-submodule::
+	After the clone is created, initialize and clone specified
+	submodules within, using their default settings. It is possible
+	to give multiple specifications by giving this argument multiple
+	times. This is equivalent to configure `submodule.defaultUpdateGroup`
+	and then running `git submodule update --init-default-path`
+	immediately after the clone is finished.
 
 --[no-]shallow-submodules::
 	All submodules which are cloned will be shallow with a depth of 1.
diff --git a/builtin/clone.c b/builtin/clone.c
index 6c80690..ef924c6 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -56,6 +56,16 @@ static struct string_list option_required_reference = STRING_LIST_INIT_NODUP;
 static struct string_list option_optional_reference = STRING_LIST_INIT_NODUP;
 static int option_dissociate;
 static int max_jobs = -1;
+static struct string_list init_submodules;
+
+static int init_submodules_cb(const struct option *opt, const char *arg, int unset)
+{
+	if (unset)
+		return -1;
+
+	string_list_append((struct string_list *)opt->value, arg);
+	return 0;
+}
 
 static struct option builtin_clone_options[] = {
 	OPT__VERBOSITY(&option_verbosity),
@@ -112,6 +122,9 @@ static struct option builtin_clone_options[] = {
 			TRANSPORT_FAMILY_IPV4),
 	OPT_SET_INT('6', "ipv6", &family, N_("use IPv6 addresses only"),
 			TRANSPORT_FAMILY_IPV6),
+	OPT_CALLBACK(0, "init-submodule", &init_submodules, N_("<pathspec>"),
+			N_("clone specific submodules. Pass multiple times for complex pathspecs"),
+			init_submodules_cb),
 	OPT_END()
 };
 
@@ -730,13 +743,21 @@ static int checkout(int submodule_progress)
 	err |= run_hook_le(NULL, "post-checkout", sha1_to_hex(null_sha1),
 			   sha1_to_hex(sha1), "1", NULL);
 
-	if (!err && option_recursive) {
+	if (!err && (option_recursive || init_submodules.nr > 0)) {
 		struct argv_array args = ARGV_ARRAY_INIT;
-		argv_array_pushl(&args, "submodule", "update", "--init", "--recursive", NULL);
+		argv_array_pushl(&args, "submodule", "update", NULL);
+
+		if (init_submodules.nr > 0)
+			argv_array_pushf(&args, "--init-default-path");
+		else
+			argv_array_pushf(&args, "--init");
 
 		if (option_shallow_submodules == 1)
 			argv_array_push(&args, "--depth=1");
 
+		if (option_recursive)
+			argv_array_pushf(&args, "--recursive");
+
 		if (max_jobs != -1)
 			argv_array_pushf(&args, "--jobs=%d", max_jobs);
 
@@ -884,6 +905,17 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		option_no_checkout = 1;
 	}
 
+	if (init_submodules.nr > 0) {
+		struct string_list_item *item;
+		struct strbuf sb = STRBUF_INIT;
+		for_each_string_list_item(item, &init_submodules) {
+			strbuf_addf(&sb, "submodule.defaultUpdatePath=%s",
+				    item->string);
+			string_list_append(&option_config,
+					   strbuf_detach(&sb, NULL));
+		}
+	}
+
 	if (!option_origin)
 		option_origin = "origin";
 
diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index 4699b1c..90f9030 100755
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -1170,4 +1170,85 @@ test_expect_success 'submodule update --init-default-path' '
 	test_cmp expect actual
 '
 
+cat <<EOF > expected
+ sub0 (test2)
+-sub1
+-sub2
+-sub3
+EOF
+
+test_expect_success 'clone --init-submodule works' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	git clone --recurse-submodules --init-submodule="sub0" multisuper multisuper_clone &&
+	(
+		cd multisuper_clone &&
+		git submodule status |cut -c 1,43- >../actual
+	) &&
+	test_cmp actual expected
+'
+
+cat <<EOF > expect
+-sub0
+ sub1 (test2)
+-sub2
+ sub3 (test2)
+EOF
+test_expect_success 'clone with multiple --init-submodule options' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	git clone --recurse-submodules \
+		  --init-submodule="." \
+		  --init-submodule ":(exclude)sub0" \
+		  --init-submodule ":(exclude)sub2" \
+			multisuper multisuper_clone &&
+	(
+		cd multisuper_clone &&
+		git submodule status |cut -c1,43- >../actual
+	) &&
+	test_cmp expect actual
+'
+
+cat <<EOF > expect
+-sub0
+ sub1 (test2)
+-sub2
+ sub3 (test2)
+EOF
+
+cat <<EOF > expect2
+-sub0
+ sub1 (test2)
+-sub2
+ sub3 (test2)
+-sub4
+ sub5 (test2)
+EOF
+
+test_expect_success 'clone and subsequent updates correctly auto-initialize submodules' '
+	test_when_finished "rm -rf multisuper_clone" &&
+	git clone --recurse-submodules --init-submodule="." \
+				       --init-submodule ":(exclude)sub0" \
+				       --init-submodule ":(exclude)sub2" \
+				       --init-submodule ":(exclude)sub4" \
+				       multisuper multisuper_clone &&
+	(
+		cd multisuper_clone &&
+		git submodule status |cut -c1,43- >../actual
+	) &&
+	test_cmp expect actual &&
+	(
+		cd multisuper &&
+		git submodule add ../sub1 sub4 &&
+		git submodule add ../sub1 sub5 &&
+		git commit -m "add more submodules"
+	) &&
+	(
+		cd multisuper_clone &&
+		# obtain the new superproject
+		git pull &&
+		git submodule update --init-default-path &&
+		git submodule status |cut -c1,43- >../actual
+	) &&
+	test_cmp expect2 actual
+'
+
 test_done
-- 
2.10.1.469.g00a8914

[PATCH 35/35] completion: clone can initialize specific submodules

[Stefan Beller]

Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 contrib/completion/git-completion.bash | 1 +
 1 file changed, 1 insertion(+)

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 21016bf..90eb772 100644
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1138,6 +1138,7 @@ _git_clone ()
 			--single-branch
 			--branch
 			--recurse-submodules
+			--init-submodule
 			"
 		return
 		;;
-- 
2.10.1.469.g00a8914

Re: [PATCH 31/35] pathspec: allow querying for attributes

[Duy Nguyen]

On Fri, Nov 11, 2016 at 3:34 AM, Stefan Beller <sbeller@google.com> wrote:
> @@ -139,7 +140,8 @@ static size_t common_prefix_len(const struct pathspec *pathspec)
>                        PATHSPEC_LITERAL |
>                        PATHSPEC_GLOB |
>                        PATHSPEC_ICASE |
> -                      PATHSPEC_EXCLUDE);
> +                      PATHSPEC_EXCLUDE |
> +                      PATHSPEC_ATTR);

Hmm.. common_prefix_len() has always been a bit relaxing and can cover
more than needed. It's for early pruning. Exact pathspec matching
_will_ be done later anyway.

Is that obvious? I'm wondering if we need to add a line or two in the
big comment code before this statement. I'm thinking it is and we
probably don't need more comments...
-- 
Duy

Re: [PATCH 31/35] pathspec: allow querying for attributes

[Stefan Beller]

On Tue, Nov 22, 2016 at 2:41 AM, Duy Nguyen <pclouds@gmail.com> wrote:
> On Fri, Nov 11, 2016 at 3:34 AM, Stefan Beller <sbeller@google.com> wrote:
>> @@ -139,7 +140,8 @@ static size_t common_prefix_len(const struct pathspec *pathspec)
>>                        PATHSPEC_LITERAL |
>>                        PATHSPEC_GLOB |
>>                        PATHSPEC_ICASE |
>> -                      PATHSPEC_EXCLUDE);
>> +                      PATHSPEC_EXCLUDE |
>> +                      PATHSPEC_ATTR);
>
> Hmm.. common_prefix_len() has always been a bit relaxing and can cover
> more than needed. It's for early pruning. Exact pathspec matching
> _will_ be done later anyway.
>
> Is that obvious?

Yes it is.
Not sure what your concern is, though.

Given the pathspec ":(attr:plumbing)Documentation/", the common_prefix_len
is still able to figure out that any match has a prefix of
strlen("Documentation/"),
no matter what attr stuff is involved, because the attr stuff is also
just reducing the
matching set.

Now if we have such a pathspec it is easier to claim common_prefix_len supports
attr as it is a correct thing to ignore the attrs completely, than to
rewrite the call to
common_prefix_len to be without attrs involved.

You *may* be able to improve it with knowledge of the attrs:
":(attr:internal-technical-api)Documentation/" may restrict the results to match
only "Documentation/technical/", but as you said, we don't have to be
exact here.

> I'm wondering if we need to add a line or two in the
> big comment code before this statement. I'm thinking it is and we
> probably don't need more comments...

Do I misunderstand the code completely here?

Thanks,
Stefan

> --
> Duy

Re: [PATCH 31/35] pathspec: allow querying for attributes

[Duy Nguyen]

On Wed, Nov 23, 2016 at 12:26 AM, Stefan Beller <sbeller@google.com> wrote:
> On Tue, Nov 22, 2016 at 2:41 AM, Duy Nguyen <pclouds@gmail.com> wrote:
>> On Fri, Nov 11, 2016 at 3:34 AM, Stefan Beller <sbeller@google.com> wrote:
>>> @@ -139,7 +140,8 @@ static size_t common_prefix_len(const struct pathspec *pathspec)
>>>                        PATHSPEC_LITERAL |
>>>                        PATHSPEC_GLOB |
>>>                        PATHSPEC_ICASE |
>>> -                      PATHSPEC_EXCLUDE);
>>> +                      PATHSPEC_EXCLUDE |
>>> +                      PATHSPEC_ATTR);
>>
>> Hmm.. common_prefix_len() has always been a bit relaxing and can cover
>> more than needed. It's for early pruning. Exact pathspec matching
>> _will_ be done later anyway.
>>
>> Is that obvious?
>
> Yes it is.
> Not sure what your concern is, though.

None really. I was just thinking out loud and trying not to make
assumptions, because I know this code quite well and I don't know how
people see this code anymore :D So all is good then.
-- 
Duy

Re: [PATCH 31/35] pathspec: allow querying for attributes

[Brandon Williams]

On 11/10, Stefan Beller wrote:
> @@ -500,6 +586,18 @@ void copy_pathspec(struct pathspec *dst, const struct pathspec *src)
>  
>  void clear_pathspec(struct pathspec *pathspec)
>  {
> +	int i, j;
> +	for (i = 0; i < pathspec->nr; i++) {
> +		if (!pathspec->items[i].attr_match_nr)
> +			continue;
> +		for (j = 0; j < pathspec->items[j].attr_match_nr; j++)

This looks like a bug.  Should it be:
  for (j = 0; j < pathspec->items[i].attr_match_nr; j++)

where items[j] -> items[i]

-- 
Brandon Williams

Re: [PATCH 31/35] pathspec: allow querying for attributes

[Brandon Williams]

On 11/10, Stefan Beller wrote:
> +static void parse_pathspec_attr_match(struct pathspec_item *item, const char *value)
> +{
>
> [...]
>
> +	if (!item->attr_check)
> +		git_attr_check_initv(&item->attr_check, attrs.argv);
> +	else
> +		die(_("Only one 'attr:' specification is allowed."));
> +
> +	argv_array_clear(&attrs);
> +	string_list_clear(&list, 0);
> +	return;
> +}

Unnecessary return statement, maybe you want to remove it?

-- 
Brandon Williams

Re: [PATCH 31/35] pathspec: allow querying for attributes

[Brandon Williams]

On 11/10, Stefan Beller wrote:
> @@ -500,6 +586,18 @@ void copy_pathspec(struct pathspec *dst, const struct pathspec *src)
>  
>  void clear_pathspec(struct pathspec *pathspec)
>  {
> +	int i, j;
> +	for (i = 0; i < pathspec->nr; i++) {
> +		if (!pathspec->items[i].attr_match_nr)
> +			continue;
> +		for (j = 0; j < pathspec->items[j].attr_match_nr; j++)
> +			free(pathspec->items[i].attr_match[j].value);
> +		free(pathspec->items[i].attr_match);
> +		if (pathspec->items[i].attr_check)
> +			git_attr_check_clear(pathspec->items[i].attr_check);
> +		free(pathspec->items[i].attr_check);
> +	}
> +
>  	free(pathspec->items);
>  	pathspec->items = NULL;

You may also want to add logic like this to the 'copy_pathspec' function
so that when a pathspec struct is copied, the destination also has
ownership of its own attribute items.

-- 
Brandon Williams

Re: [PATCH 31/35] pathspec: allow querying for attributes

[Stefan Beller]

On Mon, Nov 28, 2016 at 2:11 PM, Brandon Williams <bmwill@google.com> wrote:
> On 11/10, Stefan Beller wrote:
>> @@ -500,6 +586,18 @@ void copy_pathspec(struct pathspec *dst, const struct pathspec *src)
>>
>>  void clear_pathspec(struct pathspec *pathspec)
>>  {
>> +     int i, j;
>> +     for (i = 0; i < pathspec->nr; i++) {
>> +             if (!pathspec->items[i].attr_match_nr)
>> +                     continue;
>> +             for (j = 0; j < pathspec->items[j].attr_match_nr; j++)
>> +                     free(pathspec->items[i].attr_match[j].value);
>> +             free(pathspec->items[i].attr_match);
>> +             if (pathspec->items[i].attr_check)
>> +                     git_attr_check_clear(pathspec->items[i].attr_check);
>> +             free(pathspec->items[i].attr_check);
>> +     }
>> +
>>       free(pathspec->items);
>>       pathspec->items = NULL;
>
> You may also want to add logic like this to the 'copy_pathspec' function
> so that when a pathspec struct is copied, the destination also has
> ownership of its own attribute items.
>

Thanks for the review comments, I'll plan on resending this series after the
submodule checkout series (which is nowhere near done, but the foundation
is set with sb/submodule-intern-gitdir as a preparation.)

After discussion with Jonathan Nieder, I think it may be possible to make
this new pathspec magic work without the need for thread safety. This is
archived by constructing all relevant attr_check stacks before the preload_index
functionality (which is threaded) and then use the preconstructed attr_checks
to get attr_results just like in this series.

That approach would come with the benefit of not needing mutexes
at all inside the attr code.